Question

Which of the following is the correct factorization of the trinomial below

-7x^2-4x+20

A: (-7x+10)(x-2)
B: -1(7x-10)(x=2)
C: -7(x-5)(x+2)
D: 7(x+10)(-x+2)

Answer 1

ANSWER:

B : - 1 ( 7x - 10 ) ( x + 2 )

STEP-BY-STEP SOLUTION:

= - 7x^2 - 4x + 20

= - [ 7x^2 + 4x - 20 ]

= - [ 7x^2 + 14x - 10x - 20 ]

= - [ 7x ( x + 2 ) - 10 ( x + 2 ) ]

= - ( x + 2 ) ( 7x - 10 )

= - 1 ( 7x - 10 ) ( x + 2 )

Answer 2

A: (-7x+10)(x-2)

Explanation:

Given trinomial,

`-7x^2-4x+20`

By middle term splitting,

`=-7x^2-(14-10)x+20`

`=-7x^2-14x+10x+20`

`=-7x(x+2)+10(x+2)`

`=(-7x+10)(x+2)`

Since, further factorization is not possible,

Thus, the required factorized form of the given trinomial is,

`(-7x+10)(x+2)`

Option A is correct.