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

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 $3 a$ and $2 a$ to get $6 {a}^{2}$.

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 $3 a$ and $- 7$ to get $- 21 a$.

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

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 $6 {a}^{2} - 21 a + 2 a - 7$. We can simplify this equation by adding $2 a$ to $- 21 a$ to get $- 19 a$. This gives us our final answer of $6 {a}^{2} - 19 a - 7$.