The equation would be R(x)=35x and it would take 100 rides.
To find the point where the company breaks even we set the cost equation C(x) equal to the revenue function R(x):
15x+2000=35x
We can't have a variable on both sides, so we subtract 15x from both sides:
15x+2000-15x=35x-15x
2000=20x
Now we divide both sides by 20:
2000/20 = 20x/20
100 = x