Answer:

Step-by-step explanation:
The standard form of this equation is

m stands for the gradient or the slope, and c represents the y-intercept

The answer to this question is 40 miles per hour.
:)
The independent variable of an equation is x, or something u can change. in linear equations, for example, it is y=3x+4. and x is the independent variable cause most of the time u will plug in or substitute a number for x.