Question

Which expression is equivalent to
(
4
q
2
r
2
s
)
(
r
s
2
5
)
?


4
q
2
5


4
q
2
r
5
s


4
q
2
s
5
r


20
q
2
r
3
s
3

Answer 1

Multiply coefficients and add exponents for like bases:

(4 q^2 r^2 s)(5 r s^2) = 4·5 · q^2 · r^(2+1) · s^(1+2) = 20 q^2 r^3 s^3.

So the fourth choice is correct.