If the rational numbers a and B satisfy that a is not = 0 and a + 3B = 0, find the value of the third power of - (A / b)

If the rational numbers a and B satisfy that a is not = 0 and a + 3B = 0, find the value of the third power of - (A / b)

a+3b=0
a=-3b
-The third power of (A / b)
=-(-3)^3
=-(-27)
=27