Answer:
10r^9
Explanation:
From one of the laws of indices:
(A²)² = A ²+² = A⁴
So then, let's apply the knowledge to solve our questions.
r³ * 5r² * 2r⁴
Let's take it one after the other
= (r³ * 5r²) = 5r^5
= (r * r * r * 5 * r * r)
= (5r ^5.)(2r⁴)
=(5*2) (r^5 * r^4)
= 10 r ^9