We have the function:
• y= 360,000 - 20,000x
Where x is the number of years.
Slope-intercept form equation:
y= mx + b
Where:
m= slope
b= y-intercept ( where the line crosses the y axis)
So, for the equation given:
y= -20,000x + 360,000
a) The y-intercept is: 360,000
This means that at the beginning of the 18 years, the building is worth $360,000.(B)
For x= 0 ( at the beginning is year 0 )
y= 360,000 - 20,000 (0)
y= 360,000
b)
To find the x-intercept replace y= 0
y= -20,000x + 360,000
0 = -20,000x + 360,000
20,000x = 360,000
x= 360,000/20,000
x= 18
The x-intercept is 18
This means that the value of the building is 0 (zero) at the end of the 18 years.(A)
Replacing x= 18
y= 360,000 - 20,000(18)
y= 360,000-360,000
y= 0
c) Since the intercepts are:
y= 360,000
x= 18
The correct graph of the function is graph C