How do you simplify (x - 4)(x - 7)?

1 Answer
Jun 13, 2017

x^2-11x+28

Explanation:

We begin by doing something called FOIL in math, or "first, outside, inside, last". It is a mnemonic device to help you remember how to multiply binomials. So lets start by multiplying the first parts of each binomial.

(x-4)(x-7)

The "firsts" of this binomial product are x and x, and their product isx^2.

Next is the outsides, which are x and -7. Their product is -7x.

Now for the insides, which are -4 and x. Their product is -4x.

Lastly, the lasts, which are -4 and -7 in this case. A negative times a negative is a positive, and 4 times 7 is 28, so their product is 28.

Now to add everything together.

x^2-7x-4x+28

Simplifies to...

x^2-11x+28, which is your final answer!