SOLUTION: solve the equation(x + 3)(x - 3) = -8 solution x + 3 = -8 => x= -11 or (x-3) = -8 => x = -5 is this correct?

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: solve the equation(x + 3)(x - 3) = -8 solution x + 3 = -8 => x= -11 or (x-3) = -8 => x = -5 is this correct?      Log On


   



Question 477424: solve the equation(x + 3)(x - 3) = -8
solution
x + 3 = -8 => x= -11 or (x-3) = -8 => x = -5
is this correct?

Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
NO, it's not correct.

%28x+%2B+3%29%28x+-+3%29+=+-8...first multiply left side

x%5E2-3x%2B3x+-+9+=+-8

x%5E2-cross%283x%29%2Bcross%283x%29+-+9+=+-8

x%5E2-9+=+-8......add 8 to both sides

x%5E2-9%2B8+=+-8%2B8

x%5E2-1+=0....factor

%28x-1%29%28x%2B1%29+=0.........NOW, when you have a product equal to zero, you can find solutions:

x-1+=0.......->......x=1

x%2B1+=0.......->......x=-1


let's see it on a graph:

+graph%28+500%2C+500%2C+-10%2C10%2C+-10%2C+10%2C+%28x+%2B+3%29%28x+-+3%29+%2B8%29+