Question 615466
(2a^4-4a^3+4a^2+15a-8)+(a^5+11a^3+6a^2-4a+4)+(-5a^4+a^2-7a-7)


2a^4-4a^3+4a^2+15a-8+a^5+11a^3+6a^2-4a+4-5a^4+a^2-7a-7


(a^5)+(2a^4-5a^4)+(-4a^3+11a^3)+(4a^2+6a^2+a^2)+(15a-4a-7a)+(-8+4-7)


a^5-3a^4+7a^3+11a^2+4a-11


So (2a^4-4a^3+4a^2+15a-8)+(a^5+11a^3+6a^2-4a+4)+(-5a^4+a^2-7a-7) simplifies to  <font color="red">a^5-3a^4+7a^3+11a^2+4a-11</font>


In other words, (2a^4-4a^3+4a^2+15a-8)+(a^5+11a^3+6a^2-4a+4)+(-5a^4+a^2-7a-7) = <font color="red">a^5-3a^4+7a^3+11a^2+4a-11</font>


for all values of 'a'