Question

For the given functions f and g, find theindicated value.F(x) = x2+ 3x, g(x) =× + 2(f . g) (4)

Answer 1

Given:

`\begin{gathered} f(x)=\text{ x}^2\text{ + 3x} \\ g(x)\text{ = x + 2} \end{gathered}`

Required:

`(f\text{ .g\rparen\lparen4\rparen}`

Recall that:

`(f.g)(x)\text{ = f\lparen x\rparen. g\lparen x\rparen}`

Substituting we have:

`\begin{gathered} (f.g)(x)=\text{ \lparen x}^2\text{ + 3x\rparen\lparen x+2\rparen} \\ (f.g)(4)\text{ = \lparen4}^2\text{ + 3\lparen4\rparen\rparen\lparen4 + 2\rparen} \\ =\text{ 28 }*6\text{ } \\ =\text{ 168} \end{gathered}`

Answer: 168