How do you find 2p(a) + p(a - 1) if #p(x) = x^2 + x#? Precalculus Functions Defined and Notation Function Composition 1 Answer Ratnaker Mehta Jul 19, 2016 #2p(a)+p(a-1)=3a^2+a#. Explanation: Given poly. #p(x)=x^2+x# To find #p(a)#, we have to just put #a#, in place of #x#, Hence, #p(a)=a^2+a#, and, #p(a-1)=(a-1)^2+(a-1)=(a-1)(a-1+1)=a(a-1)#. Therefore, #2p(a)+p(a-1)=2(a^2+a)+a(a-1)=2a^2+2a+a^2-a=3a^2+a#. Answer link Related questions What is function composition? What are some examples of function composition? What are some common mistakes students make with function composition? Is function composition associative? Is it always true that #(f@g)(x) = (g@f)(x)#? If #f(x) = x + 3# and #g(x) = 2x - 7#, what is #(f@g)(x)#? If #f(x) = x^2# and #g(x) = x + 2#, what is #(f@g)(x)#? If #f(x) = x^2# and #g(x) = x + 2#, what is #(g@f)(x)#? What is the domain of #(f@g)(x)#? What is the domain of the composite function #(g@f)(x)#? See all questions in Function Composition Impact of this question 1255 views around the world You can reuse this answer Creative Commons License