Question

What are the factors of the expression below?
- x2+2x+35
A. (x - 5)(x-7)
B. (x+5)(x-7)
C. -1(x-5)(x+7)
D. -1(x+5)(x-7)

Answer 1

Answer:

(D). - ( x + 5 )( x - 7 )

Step-by-step explanation:

ax² + bx + c = a ( x - $x_{1}$ )( x - $x_{2}$ )

D = b² - 4ac

$x_{12}$ = ( - b ± √D ) ÷ 2a

~~~~~~~~~

- x² + 2x + 35 = 0

a = - 1 ; b = 2 ; c = 35

D = 4 - 4( - 1 )( 35 ) = 144

$x_{1}$ = ( - 2 - √144 ) ÷ 2 ( - 1 ) = 7

$x_{2}$ = ( - 2 + √144 ) ÷ 2 ( - 1 ) = - 5

- x² + 2x + 35 = - ( x + 5 )( x - 7 )