<p>If x and y are positive integers and 4(2^x)=2^y what is x in terms of y?
A) y-2
B) y-1
C) y
D) y+1
E) y+2</p>
<p>Answer is A</p>
<p>Well just plug in a value for x to get y.
let’s say x = 2.
so 4(2^2) = y^2
4(4) = y^2
16 = y^2
4 = y
So now that you know y and x, what is x in terms of y? well since x = 2, and y = 4, x is y-2. Thus (A).</p>
<p>You could also do it algebraically.
4(2^x) = 2^y
(2^2)(2^x) = 2^y
2^(x+2) = 2^y
Same base, therefore:
x+2 = y
x = y-2</p>
<p>Thanks guys!</p>