#### Answer

(a) Slope $= 0$ and y-intercept $=-2$
(b) See the image.
(c) Average rate of change $= 0$
(d) The linear function $G(x)=-2$ is constant.

#### Work Step by Step

Step-1: Compare the given equation with the slope-intercept form of the linear equation, that is, $G(x) = mx+b$, where $m$ is the slope of the linear function and $b$ is its y-intercept. By comparing $$G(x)=-2$$ to $$G(x) = mx+b$$ we understand that the slope of the given function is $0$, and its y-intercept is $-2$.
Note that $G(x)$ can be rewritten as $G(x) = 0\times x -2$.
Step-2: Let us put values of $x$ from $-2$ to $2$ into the function to obtain corresponding $y$ values. Using this we can plot a graph. Thus,
For $x=-2$, $G(x)=-2$
For $x=-1$, $G(x)=-2$
For $x=0$, $G(x)=-2$
For $x=1$, $G(x)=-2$
For $x=2$, $G(x) = -2$
This data obtains the graph shown.
Step-3: The average rate of change is defined as follows:
$$\frac{\Delta y}{\Delta x}=\frac{G(x_2)-G(x_1)}{x_2-x_1}$$
Let us calculate average rate of change between $x_2=2$ and $x_1=-2$,
$$\frac{\Delta y}{\Delta x}=\frac{-2-(-2)}{2-(-2)}=0$$
Step-4: Since slope $=0$, this linear function is constant.