Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Why this:
$(3 \ast (3^{k-1} + 1) - 2)$
equals to:
$(3 \ast 3^{k-1} + 3 - 2)$
and why/how from this we get to this:
$(3^k + 1)$

share|cite|improve this question
Just evaluate from left to right, giving precedence to parentheses, exponents, multiplication, division, addition, subtraction (in that order, respectively). See solomoan's answer for more specifics to your particular question. – Mr_CryptoPrime Apr 12 '11 at 9:06
up vote 0 down vote accepted

Because $a*(b+c)=a*b+a*c$ and $x^m*x^n=x^{m+n}$

share|cite|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.