6: Yes, it is linear. The constant rate of change is 
, which you can make 
. This simplifies to 15, so the constant rate of change is 15.
7. Yes, a proportional relationship exists because every output value is exactly three times every corresponding input value.
8. Yes, a proportional relationship exists because every output value is exactly
times the corresponding input value.
9. Yes, a proportional relationship exists because every y value is 7.5 times every corresponding x value, and if a line were to be drawn through the points, it would go through the origin (0,0).
7. Yes, a proportional relationship exists because every output value is exactly three times every corresponding input value.
8. Yes, a proportional relationship exists because every output value is exactly
9. Yes, a proportional relationship exists because every y value is 7.5 times every corresponding x value, and if a line were to be drawn through the points, it would go through the origin (0,0).