Question

It is known that a>0 and b<0. Compare the values of the following expressions to zero:
a^3b
-ab^3
(a+b)^2


I need help

Answer 1

a^3b
If a > 0, then a^3 > 0. (if a number is positive, then cubing it keeps it positive)
b< 0 , or b is negative
A positive times a negative yields a negative

Follow the same reasoning steps for the other two.