SOLUTION: Hello, the problem I need help on is this polynomial which I have to factor completely: a^6-81b^2 After working on the problem, I got this answer: (a^2+9b)(a^3-9b) But, the W

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Hello, the problem I need help on is this polynomial which I have to factor completely: a^6-81b^2 After working on the problem, I got this answer: (a^2+9b)(a^3-9b) But, the W      Log On


   



Question 819739: Hello, the problem I need help on is this polynomial which I have to factor completely: a^6-81b^2
After working on the problem, I got this answer: (a^2+9b)(a^3-9b)
But, the Worksheet I have says the answer is (a^3+9b)(a^3-9b). Can someone please explain?

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
polynomial which I have to factor completely: a^6-81b^2
After working on the problem, I got this answer: (a^2+9b)(a^3-9b)
But, the Worksheet I have says the answer is (a^3+9b)(a^3-9b).
:
I assume you recognized this as the "difference of squares,
Multiplying like terms you add the exponents, a^3 * a^3 = a^6
a^2 *a^3 = a^5