Question 84583
When I solved your problem, I did NOT get the same answer as the one posted by Checkley75.  Here is what I got:


{{{(a^2+2ab-b^2)(a^2-7ab+b^2)}}}

Multiply the first {{{a^2}}} times everything in the second parentheses:
{{{a^2*(a^2-7ab+b^2)=a^4-7a^3b+a^2b^2}}}


Next, multiply 2ab times everything in the second parentheses:
{{{2ab*(a^2-7ab+b^2)= 2a^3b -14a^2b^2+2ab^3}}}


Last, multiply {{{-b^2}}} times everything in the second parentheses:
{{{-b^2*(a^2-7ab+b^2)= -a^2b^2 + 7ab^3 -b^4}}}


Now, combine like terms:
{{{a^4-7a^3b + a^2b^2}}}
==> {{{ 2a^3b -14a^2b^2+2ab^3}}}
=======>      {{{-a^2b^2 + 7ab^3 -b^4}}}
__________________________________________
{{{a^4 -5a^3b -14a^2b^2 + 9ab^3 -b^4 }}}


R^2 at SCC