Answer:
y=.25x+4.75
Step-by-step explanation:
Use the equation y2 - y1 / x2 - x1 so (10-0)/(21- -19) which is 10/40, or .25.
Now you have part of the equation, y=.25x, but we need to find the b value. To do that, plug x into one of the equations, for example, (21,10). 21 x .25 = 5.25, and to get 10 we need to add 4.75, so the final equation is y=.25x+4.75