[tex] 8^{ \frac{2}{3} }=( 8^{ \frac{1}{3} })^2 =2^2=4 \\ 16^{ \frac{1}{4} } =2 \\ 9^{ \frac{1}{2} } =3 \\ 25^{- \frac{1}{2} }= \frac{1}{ 25^{ \frac{1}{2} } }= \frac{1}{5} \\ 8^{ \frac{2}{3} } - 16^{ \frac{1}{4 } }+ 9^{ \frac{1}{2} }+ 25^{- \frac{1}{2} }=4-2+3+ \frac{1}{5}=5 \frac{1}{5} [/tex]