Problem Solving

If x and y are integers and (15^x + 15^x+1)/4^y = 15^y , what is the value of x?

a.2
b.3
c.4
d.5
e.Cannot be determined

So this is what i did:

15^x + 15^x+1=15^y*4^y
15^x(1+15^1)=15^y*4^y
15^x(16)=15^y*4^y
15^x(2^4)=15^y*4^y
(3*5)^x(2^4)=(3*5)^y(2^2y)
(3^x*5^x)(2^4)=(3^y*5^y)(2^2y)

so now all the bases are same so i can equate the exponents.

x+x+4 = y+y+2y
2x+4=4y

this is where i get stuck! how do i get a value with this? Pls help!