1a:
580 - (580 × .1) - 20
580 - (58) - 20
522 - 20
502
1b:
990 - (990 × .25) - 20
990 - (247.5) - 20
742.5 - 20
722.5
I'm not sure how to solve #2.
Domain: all x values between the ends of a line on the x- axis
Range: all y values between the ends of a line on the y-axis