solve the equation log(y)/log(2) + log(y)/log(4) = 6

logy/log2 = log_2(y)

logy/log4 = log_4(y)

since 2^2 = 4, log_2(y) = 2log_4(y) = log_4(y^2)

so, now we have

log_4(y^2*y) = 6
log_4(y^3) = 6
y^3 = 4^6
y = 4^2 = 16