Joe went on a bike ride of 72 miles. He realized that if he had gone 18 mph faster, he would have arrived 9 hours sooner. How fast did he actually ride?

There is no solution to this system.

Step-by-step explanation:

To solve this problem solve the second equation for y.

2x + y = 9

y = -2x + 9

Now that we have the value of y, we can put that in for y in the first equation and solve for x.

3y = -6x + 4

3(-2x + 9) = -6x + 4

-6x + 27 = -6x + 4

27 = 4

Because this is a false statement, we know that this system has no solution.