(10*a - b)*(b + 10*a)
/ b \ / b \ 1*|a + --|*|a - --| \ 10/ \ 10/
(1*(a + b/10))*(a - b/10)
2 2 - b + 100*a
-b^2 + 100*a^2
(b + 10.0*a)*(-b + 10.0*a)