abhisheksharma85 wrote:

If x= 2^b - (8^8 + 8^6), for which of the following b values is x closest to 0?

(A) 20

(B) 24

(C) 25

(D) 30

(E) 42

Dear

abhisheksharma85,

I'm happy to help with this.

Recall the exponent rule:

(a^m)^n = a^(m*n)Therefore,

8^8 + 8^6 = (2^3)^8 + (2^3)^6 = 2^24 + 2^18

This is the thing we want to cancel with 2^b. Well, keep in mind that 2^24 is 2^6 = 64 times larger than 2^18, so for the purposes of cancelling, we will ignore the tinier number. If we want to cancel the 2^24, we need b = 24, answer =

(B).

Does all this make sense?

Mike

_________________

Mike McGarry

Magoosh Test Prep