If 2^y = 4^(5x + 3) and 3^(x - 7) = 9^y, what is the value of x + y ?
Choices:
A) -10  B) -5  C) -4  D) 3  E) 7
2^y = 4^(5x + 3)   2^y=2^2(5x+3)   y=10x+6 ........... 1   3^(x - 7) = 9^y   3^(x-7)=3^2y   x-7=2y ............. 2   put value of y=10x+6 in eq 2   x-7=2(10x+6)   x-7=20x+12   19x=-19   x=-1   therefore, y= -10+6   y=-4   x+y= -1-4= -5   Answer: -5
<result>B</result>
If 2^y = 4^(5x + 3) and 3^(x - 7) = 9^y, what is the value of x + y ?