Question

4. Factor x2 - 4x – 32.

Answer 1

Answer: (x+4)(x-8)

Explanation:

x^2 - 4x -32 Find two numbers that their product is -32 and their sum is -4. The numbers -8 and 4 will work out because -8 times 4 is -32 and -8 plus 4 is -4.

Now rewrite the whole polynomial as

x^2 +4x -8x -32 Now group them

(x^2 +4x) (-8x -32) Now factor each side

x(x +4) -8(x +4) factor out x+4

(x+4)(x-8)

Answer 2

(x - 8)(x + 4)

Explanation:

We need to find something that multiplies to 32 and adds up to 4.

The 2 special numbers would be -8 and 4.

-8(4) = -32

-8 + 4 = -4

We then simply write out the factored form:

(x - 8)(x + 4)