Is the equation 20z−5−12z=10z+8 one solution, no solution or infanate solutio?

50 points~ ! i have to turn this in tomarrow

Which of the following is best modeled using a linear equation y=ax+b, where a is less than 0?

Martha is training for a duathlon, which includes biking and running. she knows that yesterday she covered a total distance of over 55.5 miles in more than than 4.5 hours of training. martha runs at a speed of 6 mph and bikes at a rate of 15.5 mph.