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

1 Answer
Nov 13, 2016

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.