Exercise 20 Page 65

To evaluate a function for a certain value of $x$ means that we substitute the given value for every instance of $x.$ Let's do this for the given function when $x=7.$

$f(x)=\text{-}9x-2$

Substitute

$x=7$

$f(7)=\text{-}9(7)-2$

Multiply

Multiply

$f(7)=\text{-}63-2$

SubTerm

Subtract term

$f(7)=\text{-}65$

When $x=7,$ the function's value is $\text{-}65.$ The ordered pair that corresponds to this result is $(7,\text{-}65).$