Q: Find the equation of the line that has the following intercepts:
x-intercept: 5, y-intercept: -3
Answer: y = 3/5 x – 3
Explanation: The x-intercept is the point (5, 0). The y-intercept is the point (0, -3). Calculate the slope of the line passing through these points:
m= (0- -3)/(5 – 0) = 3/5
Using slope intercept form (y = mx + b), the equation is y = 3/5 x + b. We just need to find b. Or do we? We could plug in an ordered pair and solve for b, but it’s not necessary. We already have b, because in slope-intercept form, b always stands for the y-intercept. So, b = -3.
The equation is: y = 3/5 x – 3
My TI-84 Plus program ‘LINES’ will find this equation for you, given the two intercepts.