Question 758310: Hi,
How do I work out the possible values of x when the equation is (x+4)(x-4)=9
please help, thank you!x Answer by Cromlix(4381) (Show Source):
You can put this solution on YOUR website! Multiply your equation out and
collect like terms.
(x + 4)(x - 4) = 9
x^2 - 16 = 9
x^2 - 16 - 9 = 0
x^2 - 25 = 0
x = square root of 25
x = +5, -5
Proof:
Put values of x in equation.
(x + 4)(x - 4) = 9
(+5 + 4)(+5 - 4) = 9
(-5 + 4)(-5 - 4) = 9
Proved.
Hope this helps.
:-)
