SOLUTION: Use FOIL to multiply: (3x – 8)(x – 7)

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Question 165482: Use FOIL to multiply:
(3x – 8)(x – 7)
Found 2 solutions by MRperkins, Edwin McCravy:
Answer by MRperkins(300) About Me  (Show Source):
You can put this solution on YOUR website!
FOIL means First Outer Inner Last
Think of it like this (a+b)(c+d)=first(a*c)+outer(a*d)+inner(b*c)+last(b*d)
for your problem:
a=3x
b=-8
c=x
d=-7
.
If you substitute your numbers into the above equation then you will have your answer.
.
If you need additional help just contact me @ justin.sheppard.tech@hotmail.com
.
hopefully this helps

Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
Edwin's solution:
Use FOIL to multiply:


(3x – 8)(x – 7)

You can make four pairs out of that:

The F in "FOIL" stands for "FIRSTS"
The red ones below are the Firsts

(3x – 8)(x – 7)

That's because the 3x comes FIRST in the (3x - 8)
and x comes first in (x - 7)

So when we multiply the FIRSTS we get (3x)(x) or 3x2

-----------------

The O in "FOIL" stands for "OUTERS"
The red ones below are the Outers:

(3x – 8)(x – 7)

That's because the 3x is on the extreme left and
-7 is on the extreme right.  So they are said to
be on the outside.

So when we multiply the OUTERS we get (3x)(-7) or -21x.

-----------------
 
The I in "FOIL" stands for "INNERS"
The red ones below are the INNERS:

(3x – 8)(x – 7)

That's because the -8 and the x are in
the middle.  So they are said to
be on the INside.

So when we multiply the INNERS we get (-8)(x) or -8x.

---------------

The L in "FOIL" stands for "LASTS"
The red ones below are the Lasts

(3x – 8)(x – 7)

That's because the -8 comes LAST in the (3x - 8)
and -7 comes LAST in (x - 7)

When we multiply the LASTS we get (-8)(-7) or +56.

So when we write out what we have:

FIRSTS:  3x2 
OUTERS:  -21x
INNERS:  -8x
LASTS:   +56

So we get 

3x2-21x-8x+56

The terms -21x and -8x then combine to give -29x, and so we
have as a final answer:

3x2-29x+56
 
Edwin