Question 713438
-(4x)^(2)x(5x^(3))

Multiply - by x to get -x.
(-x)(4x)^(2)(5x^(3))

Squaring a number is the same as multiplying the number by itself (4*4).  In this case, 4 squared is 16.
(-x)*16x^(2)(5x^(3))

Multiply 16x^(2) by each term inside the parentheses.
-80x^(6)