Question

What's the rate of change of y=4x+7?

Answer 1

The slope/growth is 4.
Y= 4x+7
Figure 0 / y intercept= 7
The slope / growth = 4

Answer 2

Since this is a linear equation the rate of change or velocity is constant.  Take the derivative of y with respect to x...

dy/dx=4

This is commonly called the slope of the line.  All lines because they are straight have a constant velocity.