BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

generally expo factoring

Expert replies
by smallsorrow » Tue Oct 14, 2008 11:51 pm
I know this might be annyoing... but I have a question which no book so far could answer:
There is a factoring "trick", which is e.g.
2^(x)+2^(x-1) = 2^x-2 (2^2+1) - can anybody explain the rule behind this?
Thank you very much!!
Join the discussion
Source: — Problem Solving |

by stop@800 » Wed Oct 15, 2008 12:12 am
No logic required, you just need to take out common part :)

2^x + 2^(x-1)

4 * (2^(x-2)) + 2 * (2^(x-2))

2^(x-2) [4 + 2]

Please see if you have made any typo

The answer should be
2^x-2 (2^2+2)
Join the discussion

by raunekk » Wed Oct 15, 2008 1:04 am
i agree with stop@800,,,

there should be 2 in place of 1
Join the discussion

by smallsorrow » Wed Oct 15, 2008 7:11 am
me and the typos - you are right its a 2
Join the discussion

hey i feel like a retard

by ehimare » Thu Oct 16, 2008 3:12 am
can you explain this step

2^x + 2^(x-1)

4 * (2^(x-2)) + 2 * (2^(x-2))
Join the discussion