The table represents the interest rates, r, at various years and the corresponding median house value, v. What does the slope of the trend line equation v = 2.4r + 154 represent?

The answer is c. v=2.4r+154. v is the dependent variable, and r is the independent variable. From the equation above, if we increase r by 1 unit, v will increase by 2.4 (154 doesn't affect because it's always a constant). The unit of r is %, while the unit of v is thousand, therefore if we increase interest rate by 1%,  the median house value increases by 2.4 thousand.