You have to do 2 to the third power and then 5 to the second power then times them both to get your answer which is 200^5.
8(3x⁵) - (2x)³(5x²)
→ 8(3x⁵) = 24x⁵
→ (2x)³(5x²) = (2x)(2x)(2x)(5xx) = (2*2*2*5)(xxxxx) = 40x⁵
24x⁵ - 40x⁵
= (24 - 40) x⁵
= -16x⁵