Tough and Tricky questions: Exponents.
If 5^(x+1)*4^(y-1) = 25^x*64^y, then x + y =  Choices:
A) 3/2 B) -1/2 C) -1 D) 1/2 E) 2/3
Here is my solution.   5^(x+1)*4^(y-1) = 25^x*64^y   Here RHS 25^x*64^y= 5^(2x)*4^(3y)   Equating powers on both sides--&gt;   x+1=2x , thus x=1 and   2y-1=3y giving y=-1/2   So, x+y=1/2   Option: 1/2
<result>D</result>
Tough and Tricky questions: Exponents.
If 5^(x+1)*4^(y-1) = 25^x*64^y, then x + y =