Answer:
1. The required slope m, for the context is

2. The y-intercept in the context is

3. The graph is on Desmos.
Explanation:
Given:

Where,
a is the speed of sound wave.
t is the air temperature.
This is a linear model type equation.
Can be represented in the slope intercept form which is equal to

Where,
m = Slope of the line.
c = y-intercept.
Now if we compare the given model by slope intercept formula we get

So ,the slope in the context of the problem is
.
and the y intercept in the context of the problem

For Sketching the graph we require two point
put t = 0
∴ a = 1052
Let A (1052, 0) be one point.
put a = 0
∴ t = -974.07
Let B (0, -974.07) another point.
So, the x intercept of the linear model is

Here in the graph
X axis represent temperature in degree, Fahrenheit.(t)
Y axis represent Speed of sound wave in feet per second.(a)
Scale on both axes:
1 cm = 100 feet per second on y-axis
1 cm = 100 degree Fahrenheit on x-axis