Step-by-step explanation:
To answer this question, we have to use the same equation for each payment plan:
1. y = 20x + 50
2. y = 15x + 80
If x = 12, answer to the first equation would be y = 290
20 x 12 = 240 and 240 + 50 = 290
And the answer to the second equation would be y = 260
15 x 12 = 180 and 180 + 80 = 260
So, the second payment plan is cheaper by 30 dollars!