Question

If a/b = -3/7^9 ÷ -3/7^8, the value of (a/b)^3 is​

Answer 1

Answer:

We have (a+b)3=a3+b3+3ab(a+b)

∴a3+b3=(a+b)3−3ab(a+b)

=(9)3−3×20(9)

=729−540=189

∴a3+b3=189