(2*a + 5*b)*(5*a - 2*b)
/ 5*b\ / 2*b\ 1*|a + ---|*|a - ---| \ 2 / \ 5 /
(1*(a + 5*b/2))*(a - 2*b/5)
(2.0*a + 5.0*b)*(5.0*a - 2.0*b)
2 2 - 10*b + 10*a + 21*a*b
-10*b^2 + 10*a^2 + 21*a*b