Which statement about f(x) = x2 + 4x – 21 is true? A. The zeros are – 7and -3, because f (x) = (x + 7)(x + 3)
B. The zeros are 3 and 7, because f(x) = (x – 3)(x – 7)
C.
The zeros are –3 and 7 , because f(x) = (x+3)(x – 7)
D.
The zeros are –7and 3 , because f(x) = (x – 3)(x + 7)

you can't solve x because it is 2 linear equation and you only have one equation

option 3 . (5x + 1) - (-10x + 6)

step-by-step explanation:

option 1 :

(4x + 3) + (-9x + 4)

or 4x+3 -9x + 4

or -5x + 7

option 2

(x - 2) - (6x - 9)

or x-2-6x + 9

or -5x + 7

option 3

(5x+ + 6)

or 5x + 1 + 10x -6

or 15x -5

option 4

-4x+2x+7-3x

-7x + 2x + 7

-5x + 7

hence only option 3 did   not satisfy the given simplify expression.