Question 203742
(-1x^2y^5)^4 * (-1x^2y^4)^5
.
x^8y^20 * -1 * x^10y^20
.
   ( -x^18 y^40)
.
check,  let  x=1,,y=2,,,,,in  both original  and  snswer,,-2^40,,,ok