How do you multiply #(3a + 1) ( 2a - 7)#?

1 Answer
Nov 13, 2016

Answer:

Use the FOIL method.

Explanation:

FOIL stands for:

Firsts
Outsides
Insides
Lasts

These refer to the position of the terms in the binomials. Let's start solving by multiplying the Firsts. In this case, we would multiply #3a# and #2a# to get #6a^2#.

Next, let's multiply the Outsides, which are the first term of the first binomial and the second term of the second binomial. We would multiply #3a# and #-7# to get #-21a#.

We'll multiply the Insides next. These would be #1# and #2a#, which we would multiply to get #2a#.

Finally, we multiply the Lasts, which are #1# and #-7#, to get #-7#.

We now have to put them all together in one expression. Our expression is #6a^2-21a+2a-7#. We can simplify this equation by adding #2a# to #-21a# to get #-19a#. This gives us our final answer of #6a^2-19a-7#.