6: Yes, it is linear. The constant rate of change is [tex] \frac{ y_{2}- y_{1} }{ x_{2}- x_{1} } [/tex], which you can make [tex] \frac{175-100}{10-5} [/tex]. 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 [tex] \frac{3}{8} [/tex] 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).
