How do you find the coefficient of x^2 in the expansion of (2+x)^5? Precalculus The Binomial Theorem Pascal's Triangle and Binomial Expansion 1 Answer Euan S. Aug 13, 2016 80 Explanation: Binomial theorem: (x+y)^n = sum_(k=0)^n ((n),(k)) x^(n-k)y^k (x+2)^5 = sum_(k=0)^5((5),(k)) x^(5-k)2^k Looking for x^2 so look at the k=3 term: ((5),(3))x^2*2^3 = 8*(5!)/(3!2!)x^2 = 80x^2 Answer link Related questions What is Pascal's triangle? How do I find the nth row of Pascal's triangle? How does Pascal's triangle relate to binomial expansion? How do I find a coefficient using Pascal's triangle? How do I use Pascal's triangle to expand (2x + y)^4? How do I use Pascal's triangle to expand (3a + b)^4? How do I use Pascal's triangle to expand (x + 2)^5? How do I use Pascal's triangle to expand (x - 1)^5? How do I use Pascal's triangle to expand a binomial? How do I use Pascal's triangle to expand the binomial (a-b)^6? See all questions in Pascal's Triangle and Binomial Expansion Impact of this question 5182 views around the world You can reuse this answer Creative Commons License