Question

X^2– 7x- 18
(Factor the following))

Answer 1

(x - 9)(x + 2)

x = 9 or -2

Explanation:

First, we need to find factors of 18 that add up to -7

Factors of 18:

1 and 18

2 and 9

3 and 6

Add/Subtract them to have a total sum of -7

18 - 1 = 17 ...... 1 - 18 = -17 (not -7)

9 - 2 = 7 ........ 2 - 9 = -7 (sum of -7)

6 - 3 = 3 ......... 3 - 6 = -3 . (not -7)

Hence the numbers that would go in the brackets would be -9 and 2

(x - 9)(x + 2)

x² - 7x - 18

Answer 2

(x-9)(x+2)

Explanation:

The first term is the product of two x's being multiplied together. the second term (-7x) is the sum of the two numbers. -18 (the third term) is the product of those numbers.

Think: what two numbers will add up to -7 and multiply to -18

Those numbers are -9 and 2

Now, this is a quadratic trinomial, and you factor these kinds of equations like this: (x+a)(x+b) (a and b as placeholders for actual numbers)

Now, plug -9 and 2 in

(x-9)(x+2)

Hope this helps!