Answer:
16x^3 +64x^2 -40x
Step-by-step explanation:
Use the distributive property. The factor outside parentheses multiplies each term inside parentheses:
8x(2x^2 +8x -5) = (8x)(2x^2) +(8x)(8x) +(8x)(-5)
= 16x^3 +64x^2 -40x