Which expression is equivalent to 9x - (x - 3) (x + 1) + 10x?

-x2 + 19x+8

O - x2+26x+8

8x2 + 10x+8

8x2 + 26x+8

9x - (x-3) (x+1) + 10x

Solving (x-3) (x+1) first

it implies x (x+1) - 3 (x+1)

= x^2 + x - 3x - 3

= x^2 - 2x - 3

return the result into the original question

it gives: 9x - (x^2 - 2x - 3) + 10x

expand

9x - x^2 + 2x+3 + 10x

collect the like terms

- x^2 + 21x + 3

-x^2 + 21x + 3.

Step-by-step explanation:

9x - (x - 3) (x + 1) + 10x

= 19x - (x^2 - 2x - 3)

= - x^2 + 2x + 19x + 3

= - x^2 + 21x + 3.