Prerequisites - P.2 - Exponents and Radicals - Exercises - Page 24: 16

$\dfrac{7}{16}$

Given: $x=4$ Need to solve $7x^{-2}$ By using quotient property it can be re-written as: $7x^{-2}=\dfrac{7}{x^2}$ Plug the value of $x=4$ in $\dfrac{7}{x^2}$ $\dfrac{7}{x^2}=\dfrac{7}{(4)^2}=\dfrac{7}{16}$