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

2 Answers
Jun 25, 2016

Answer:

#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#

Jun 25, 2016

Answer:

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)