EXPONENTS

[sogmat]

If 2^x + 2^x + 2^x + 2^x = 2^n, what is x in terms of n?
A. n/4
B. 4n
C. 2n
D. n - 2
E. n + 2

[vishubn]

2^x(1+1+1+1)
2^x*2^2

2^x+2=2^n

n=x+2

x=n-2

D

vishu

[VP_Jim]

Another good way to do this problem is to plug in numbers for x. If we plug in 2 for x, we get:

16=2^n
So, n = 4

If n=4 and x=2, x in terms for n is answer choice D, n-2.

Note that plugging in any number will work - x=1, x=3, etc.