Question

In the following exercises, evaluate the function at:

$$\begin{gathered} a.f\left(2\right) \\ b.f(-1) \\ c.f\left(a\right) \end{gathered}$$

Function:$f\left(x\right)=3x+4$

Short answer

a. The value of the function at $x=2$is $10$.

b. The value of the function at $x=-1$is $1$.

c. The value of the function at$x=a$is$3a+4.$

Step-by-step solution

Step 1. Given Information

The given function is$f\left(x\right)=3x+4$

Part (a) Step 1. Evaluating the function at x=2.

To evaluate$f\left(2\right)$, substitute $2$for $x.$

$$\begin{gathered} f\left(2\right)=3\left(2\right)+4 \\ f\left(2\right)=6+4 \\ f\left(2\right)=10 \end{gathered}$$$f\left(2\right)=10$

Part (b) Step 1. Evaluating the function at x=-1.

To evaluate $f(-1),$substitute $-1$for$x.$

$$\begin{gathered} f(-1)=3(-1)+4 \\ f(-1)=-3+4 \\ f(-1)=1 \end{gathered}$$

Part (c) Step 1. Evaluating the function at x=a.

To evaluate $f\left(a\right)$substitute $a$for $x.$

$$\begin{gathered} f\left(a\right)=3\left(a\right)+4 \\ f\left(a\right)=3a+4 \end{gathered}$$

Step 5. Conclusion

Therefore, we have,

$$\begin{gathered} a.f\left(2\right)=10 \\ b.f(-1)=1 \\ c.f\left(a\right)=3a+4 \end{gathered}$$