Question

Which of the following is the complete factorization of 3x2-6x-240?

Answer 1

1. Reduce 3x2-6x-240 to x^2 - 2x - 80

2. Use " ^ " to indicate exponentiation

3. Factor x^2 - 2x - 80 using completing the square:

x^2 - 2x + 1^2 - 1^2 - 80

(x+1)^2 - 1 - 80

(x+1)^2 - 81

(x+1)^2 - 9^2 = (x+1-9)(x+1 +9), or (x-8)(x+10)

Final answer, with all factors shown: 3(x-8)(x+10)

Explanation:

Answer 2

1. Reduce 3x2-6x-240 to x^2 - 2x - 80

2. Use " ^ " to indicate exponentiation

3. Factor x^2 - 2x - 80 using completing the square:

x^2 - 2x + 1^2 - 1^2 - 80

(x+1)^2 - 1 - 80
(x+1)^2 - 81
(x+1)^2 - 9^2 = (x+1-9)(x+1 +9), or (x-8)(x+10)

Final answer, with all factors shown: 3(x-8)(x+10)