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Let's do some problems with
the distributive property.
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And the distributive property
just essentially reminds us
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that if we have, let's say, a
times b plus c, and then we
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need to multiply a times this,
we have to multiply a times
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both of these numbers.
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So this is going to be equal to
a times b plus a times c.
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It will not be just a
times b then plus c.
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And that makes complete sense.
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Let me give you an example.
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If I had said 5 times 3 plus
7, now, if you were to work
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this out using order of
operations, you'd say, this is
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5 times 10.
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So you'd say, this is 5 times
10, which is equal to 50.
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And we know that that's
the right answer.
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Now, use the distributive
property, that tells us that
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this is going to be equal to 5
times 3, which is 15, plus 5
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times 7, which is 35.
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And 15 plus 35 is
definitely 50.
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If you only multiplied the 5
times the 3, you'd have 15,
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and then plus the seven, you'd
get the wrong answer.
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You're multiplying 5 times
these things, you have to
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multiply 5 times both
of these things.
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Because you're multiplying
the sum of these guys.
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Anyway.
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Let's just apply that to a
sampling of these problems.
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Let's do A.
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So we have 1/2 times
x minus y minus 4.
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Well, we multiply 1/2
times both of these.
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So it's going to be 1/2
x minus 1/2 y minus
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4, and we're done.
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Let's do C.
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We have 6 plus x
minus 5 plus 7.
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Well, here there's actually
no distributive
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property to even do.
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We can actually just remove
the parentheses.
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6 plus this thing, that's the
same thing as 6 plus x plus
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negative 5 plus 7.
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Or you could view this
as 6 plus-- So this
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right here is 2, right?
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Negative 5 plus 7 is 2,
2 plus 6 is 8, so it
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becomes 8 plus x.
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All right.
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Not too bad.
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That was C.
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Let's do E.
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We have 4 times m plus 7 minus
6 times 4 minus m.
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Let's do the distributive
property.
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4 times m is 4m plus
4 times 7 is 28.
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And then we could
do it two ways.
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Let's do it this way first.
So we could have minus
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6 times 4 is 24.
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6 times negative
m is minus 6m.
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And notice, I could have just
said, times negative 6, and
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have a plus here, but I'm
doing it in two steps.
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I'm doing the 6 first, and then
I'll do the negative 1.
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And so this is going to be
4m plus 28, and then you
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distribute the negative sign.
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You can view this as a negative
1 times all of this.
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So negative 1 times
24 is minus 24.
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Negative 1 times minus
6m is plus 6m.
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Now you add the m terms.
4m plus 6m is 10m.
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And then add the constant terms.
28 minus 24, that is
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equal to plus 4.
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Let's go down here.
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Use the distributive property
to simplify
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the following fractions.
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So I'll do every other
one again.
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So the first one is, a
is 8x plus 12 over 4.
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So the reason why they're
saying the distributive
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property, you're essentially
saying, let's divide this
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whole thing by 4.
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And to divide the whole thing by
4, you have to divide each
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of the things by 4.
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You could even view this as,
this is the same thing as
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multiplying 1/4 times
8x plus 12.
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These two things
are equivalent.
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Here you're dividing each
by 4, here you're
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multiplying each by 4.
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If you did it this way, this is
the same thing as 8x over 4
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plus 12 over 4.
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You're kind of doing a adding
fractions problem in reverse.
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And then this 8 divided
by 4 is going to be,
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this'll be 2x plus 3.
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That's one way to do it.
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Or you could do it this way.
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1/4 times 8x is 2x, plus
1/4 times 12 is 3.
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Either way, we got
the same answer.
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C.
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We have 11x plus 12 over 2.
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Just like here.
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We could say, this is the same
thing as 11-- We could write
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it as 11 over 2x, if we like.
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Or 11x over 2, either way.
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Plus 12 over 2 plus 6.
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And let's just do one more.
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E.
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This looks interesting.
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We have a negative out in front,
and then we have a 6z
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minus 2 over 3.
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So one way we can view this,
this is the same thing, this
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is equal to, negative 1/3
times 6z minus 2.
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These two things
are equivalent.
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Right?
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This is a negative 1/3.
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You could imagine a
1 right out here.
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Right?
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Negative 1/3 times 6z minus 2.
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And then you just do the
distributive property.
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Negative 1/3 times 6z is
going to be minus 2z.
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And then negative 1/3 times
negative 2, negatives cancel
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out, you get plus 2/3.
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And you are done.
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