SOLUTION: I really need help. If (y^a * y^a)^3 = (y)^a-4, what is the value of a? thank you

Algebra ->  Equations -> SOLUTION: I really need help. If (y^a * y^a)^3 = (y)^a-4, what is the value of a? thank you      Log On


   

Question 714628: I really need help.
If (y^a * y^a)^3 = (y)^a-4, what is the value of a?
thank you
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

%28y%5Ea+%2A+y%5Ea%29%5E3+=+y%5E%28a-4%29
%28y%5E%28a%2Ba%29%29%5E3+=+y%5E%28a-4%29
%28y%5E%282a%29%29%5E3+=+y%5E%28a-4%29
%28y%5E%282a%29%2A3%29+=+y%5E%28a-4%29
y%5E%286a%29+=+y%5E%28a-4%29.....if the bases equal, exponents are equal too; so, we have

6a+=+a-4...solve for a

6a-a+=+-4

5a+=+-4

a+=+-4%2F5