SOLUTION: We have been working on factoring trinomials and the problem I don't know how to solve is (x^2+4x-4)^2=64. I think what we're supposed to do is divide the exponent off both sides b

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: We have been working on factoring trinomials and the problem I don't know how to solve is (x^2+4x-4)^2=64. I think what we're supposed to do is divide the exponent off both sides b      Log On


   



Question 354730: We have been working on factoring trinomials and the problem I don't know how to solve is (x^2+4x-4)^2=64. I think what we're supposed to do is divide the exponent off both sides but I'm not sure. Were I get stuck is you're left with x^2+4x-4 on one side and that doesn't facter into two binomials. HELP ME!
Found 2 solutions by scott8148, Edwin McCravy:
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
taking square root ___ x^2 + 4x - 4 = ±8

x^2 + 4x - 4 = 8 ___ x^2 + 4x - 12 = 0

x^2 + 4x - 4 = -8 ___ x^2 + 4x + 4 = 0

now factor both ...



Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!
%28x%5E2%2B4x-4%29%5E2=64
We use the principle of square roots:

Take away the square on the right, take ± square roots of the right side

x%5E2%2B4x-4=%22%22+%2B-+sqrt%2864%29

x%5E2%2B4x-4=%22%22+%2B-+8

Make two equations, one with the + and one with the -

x%5E2%2B4x-4=%22%22%2B8 and x%5E2%2B4x-4=-8

Solving the first one

x%5E2%2B4x-4=%22%22%2B8

Get 0 on the right:

x%5E2%2B4x-12=0

Factor the left side by thinking of two whole numbers which
have product 12 and difference 4.  They are 6 and 2.  So
we write

%22%28x%22 %226%29%28x%22 %222%29%22=0

Then we put in the signs so that if we were to FOIL it out
we would get the middle term %22%22%2B4x in the middle.

%28x%2B6%29%28x-2%29=0

Then we use the zero-factor principle:

set each factor = 0

x%2B6=0 gives solution x=-6

x-2=0 gives solution x=2

-------------------

Solving the second one

x%5E2%2B4x-4=-8

Get 0 on the right:

x%5E2%2B4x%2B4=0

Factor the left side by thinking of two whole numbers which
have product 4 and sum 4.  They are 2 and 2.  So
we write

%22%28x%22 %222%29%28x%22 %222%29%22=0

Then we put in the signs so that if we were to FOIL it out
we would get the middle term %22%22%2B4x in the middle.

%28x%2B2%29%28x%2B2%29=0

Then we use the zero-factor principle:

set each factor = 0

x%2B2=0 gives solution x=-2

The second factor is the same, so we do not get an additional solution.

Checking in the original equation:

Checking x=-6

%28x%5E2%2B4x-4%29%5E2=64

%28%28-6%29%5E2%2B4%28-6%29-4%29%5E2=64
%2836-24-4%29%5E2=64
%288%29%5E2=64
64=64

Checking x=2

%28x%5E2%2B4x-4%29%5E2=64

%28%282%29%5E2%2B4%282%29-4%29%5E2=64
%284%2B8-4%29%5E2=64
%288%29%5E2=64
64=64

Checking x=-2

%28x%5E2%2B4x-4%29%5E2=64

%28%28-2%29%5E2%2B4%28-2%29-4%29%5E2=64
%284-8-4%29%5E2=64
%28-8%29%5E2=64
64=64

They are all solutions.

Edwin