Answer:
3 horas si se toma apartir de lo que se dice en el problema
Input: 4y-16+8y=-4 answer: 12y-16=-4 HERE IS YOUR ANSWER
The common ratio is 1/2 and the first term is 32
f(x)=A1×(common ratio)^x-1
f(x)=32×(1/2)^x-1
Your answer is D.

Actually Welcome to the Concept of the Properties of indices.
Here, we have to prove that, if the above exponential equation are equal or not., let's prove it
1.)L.H.S
a^12*a^4 = a^m*a^n ===> a^(m+n)
hence, a^(12+4) ===> a^(16)
2.) R.H.S
===> a^8*a^8 = a^(8+8) ==> a^(16)
since here, LHS = RHS
so both are equal.