Question

How do you factor `2x^2-2x-84`?

Answer 1

`2(x^2-x-42)`

Explanation:

when factorising you find a common multiple of all the digits. In this case we have `2`. `x` does not go into `84`. We then use factorisation `2(x^2-x-42)`.

Double checking our work
`2(x^2)= 2x^2`
`2(x)= 2x`
`2(42) = 8`

Therefore = `2x^2-2x-84`

Answer 2

2(x + 6)(x - 7)

Explanation:

`y = 2(x^2 - x - 42).`
Factor the trinomial in parentheses.
Find 2 numbers knowing their sum (b = -1) and their product (c = -42)
They are: 6 and -7.
Sum: 6 - 7 = -1
Product: 6(-7) = -42
y = 2(x + 6)(x - 7)