I am showing the algebraic approach, you can also plug-in the answer choices to get the right answer.kriti87 wrote:Hi,
I could not find any solutions to this problem anywhere in the forums.
Please help.
2^x - 2^(x-2) = 3(2^13), what is x?
A) 9
B) 11
C) 13
D) 15
E) 17
2^x - 2^(x-2) = 3(2^13)
2^x[1 - 2^(-2)] = 3(2^13)
2^x[1 - 1/4] = 3(2^13)
2^x * (3/4) = 3(2^13
2^x * 3 * 2^(-2) = 3(2^13)
2^(x - 2) * 3 = (2^13) * 3
Since the bases are the same on both sides, so equating the exponents,
x - 2 = 13 implies x = 15
The correct answer is D.
