(9*c + 5)*(c*(-9) + 9)
(5 + 9*c)*(9 - 9*c)
(5.0 + 9.0*c)*(9.0 - 9.0*c)
9*(1 - c)*(5 + 9*c)
2 45 - 81*c + 36*c
-9*(-1 + c)*(5 + 9*c)