SOLUTION: Please help me understand this: (x+9)^2=64 I tried this: (x+9)^2=64 x^2+81=64 I'm not sure what to do from here. Do you subtract 81 from both sides or subtract 64? If you

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Please help me understand this: (x+9)^2=64 I tried this: (x+9)^2=64 x^2+81=64 I'm not sure what to do from here. Do you subtract 81 from both sides or subtract 64? If you      Log On


   

Question 729512: Please help me understand this:
(x+9)^2=64
I tried this:
(x+9)^2=64
x^2+81=64
I'm not sure what to do from here.
Do you subtract 81 from both sides or subtract 64?
If you subtract 81 then it will be x^2=-17; how do I solve this?
I cannot use the quadratic function because the number you have to square root it by is a negative number and we haven't learned that yet so I don't think that is right.
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!

you tried this:
%28x%2B9%29%5E2=64
x%5E2%2B81=64..this is incorrect %28x%2B9%29%5E2=x%5E2%2B18x%2B81 not x%5E2%2B81
try it this way:
%28x%2B9%29%5E2=64+
%28x%2B9%29%5E2=8%5E2+....since exponents same, bases are same to, so we have
%28x%2B9%29=8+.....solve for x
x=8-9+
x=-1+
check:
%28-1%2B9%29%5E2=64+
%288%29%5E2=64+
64=64+