Answer:
Hey there !
• let f(x) be:
[tex]{ \tt{f(x) = 7 {x}^{2} - 3x - 6}}[/tex]
• substitute x as 3:
[tex]{ \tt{f(3) = 7 {(3)}^{2} - 3(3) - 6 }} \\ \\ { \tt{f(3) = 63 - 9 - 6}} \\ \\ \dashrightarrow \: { \underline{ \underline{ \tt{ \: \: f(3) = 48 \: \: }}}}[/tex]
