Math Snap
PROBLEM
Bob bought a house for $ 42,000. Now it's worth $ 67,500.
(a) Find and in for .
(b) Estimate when the house will be worth $ 72,500.
STEP 1
Assumptions1. The initial value of the house is 67,5003. The value of the house changes linearly over time4. The linear equation representing the value of the house is , where is the value of the house, is the slope of the line (rate of change of the house's value), is the time in years, and is the y-intercept (initial value of the house)
STEP 2
First, we need to find the slope of the line. The slope is the rate of change of the house's value over time. It can be found by subtracting the initial value of the house from its value8 years later, and then dividing by the time difference.
STEP 3
Now, plug in the given values for the initial value of the house, its value8 years later, and the time difference to calculate the slope.
m = \frac{\($\)67,500 - \($\)42,000}{8\, years -0\, years}
STEP 4
Calculate the slope.
m = \frac{\($\)67,500 - \($\)42,000}{8} = \($\)3,187.\, per\, year
STEP 5
The y-intercept is the initial value of the house, which is given as $42,000.
b = \($\)42,000
STEP 6
Now that we have the slope and the y-intercept , we can write the linear equation representing the value of the house.
STEP 7
Plug in the values for and to write the equation.
V = \($\)3,187.5t + \($\)42,000
STEP 8
To estimate in how many years after purchase the house will be worth V72,500 in the equation and solve for .
\($\)72,500 = \($\)3,187.5t + \($\)42,000
STEP 9
Subtract t$.
\($\)72,500 - \($\)42,000 = \($\)3,187.5t
STEP 10
Divide both sides of the equation by t$.
t = \frac{\($\)72,500 - \($\)42,000}{\($\)3,187.5}
SOLUTION
Calculate the value of .
t = \frac{\($\)72,500 - \($\)42,000}{\($\)3,187.5} \approx9.6\, yearsSo, the house will be worth $72,500 approximately9.6 years after it was purchased.