Question

a)\(\frac{9^{11}-9^{10}-9^9}{639}\)

b)\(\frac{\left(5^4-5^3\right)^3}{125^4}\)

 

Answer 1

\(\frac{9^{11}-9^{10}-9^9}{639}\)

\(=\frac{9^9\left(9^2-9-1\right)}{639}\)

\(=\frac{9^8\left(9^2-9-1\right)}{71}\)

\(=\frac{9^8.71}{71}\)

\(=9^8\)

Answer 2

\(\frac{\left(5^4-5^3\right)^3}{125^4}\)

\(\frac{\left[5^3.4\right]^3}{125^4}\)

\(\frac{5^9.4^3}{5^{12}}\)

\(\frac{4^3}{5^3}\)