Solving Quadratic equations:x^2 + 9x + 9 = 0
How would I solve this?

You can complete the square:

x² + 9x + 9 = x² + 9x + 81/4 - 45/4

x² + 9x + 9 = x² + 2•(9/2)x + (9/2)² - 45/4

x² + 9x + 9 = (x + 9/2)² - 45/4

Now set this equal to 0 and solve for x :

(x + 9/2)² - 45/4 = 0

(x + 9/2)² = 45/4

|x + 9/2| = 3/2 √5

x + 9/2 = 3/2 √5   or   x + 9/2 = - 3/2 √5

x = -(9 - 3√5)/2   or   x = -(9 + 3√5)/2

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.