Examples
(0,9)(0,9) , (8,6)(8,6)
Step 1
Use y=mx+by=mx+b to calculate the equation of the line, where mm represents the slope and bb represents the y-intercept.
To calculate the equation of the line, use the y=mx+by=mx+b format.
Step 2
Slope is equal to the change in yy over the change in xx, or rise over run.
m=(change in y)(change in x)m=(change in y)(change in x)
Step 3
The change in xx is equal to the difference in x-coordinates (also called run), and the change in yy is equal to the difference in y-coordinates (also called rise).
m=y2-y1x2-x1m=y2−y1x2−x1
Step 4
Substitute in the values of xx and yy into the equation to find the slope.
m=6-(9)8-(0)m=6−(9)8−(0)
Step 5
Step 5.1
Simplify the numerator.
Step 5.1.1
Multiply -1−1 by 99.
m=6-98-(0)m=6−98−(0)
Step 5.1.2
Subtract 99 from 66.
m=-38-(0)m=−38−(0)
m=-38-(0)m=−38−(0)
Step 5.2
Simplify the denominator.
Step 5.2.1
Multiply -1−1 by 00.
m=-38+0m=−38+0
Step 5.2.2
Add 88 and 00.
m=-38m=−38
m=-38m=−38
Step 5.3
Move the negative in front of the fraction.
m=-38m=−38
m=-38m=−38
Step 6
Step 6.1
Use the formula for the equation of a line to find bb.
y=mx+by=mx+b
Step 6.2
Substitute the value of mm into the equation.
y=(-38)⋅x+by=(−38)⋅x+b
Step 6.3
Substitute the value of xx into the equation.
y=(-38)⋅(0)+by=(−38)⋅(0)+b
Step 6.4
Substitute the value of yy into the equation.
9=(-38)⋅(0)+b9=(−38)⋅(0)+b
Step 6.5
Find the value of bb.
Step 6.5.1
Rewrite the equation as -38⋅0+b=9−38⋅0+b=9.
-38⋅0+b=9−38⋅0+b=9
Step 6.5.2
Simplify -38⋅0+b−38⋅0+b.
Step 6.5.2.1
Multiply -38⋅0−38⋅0.
Step 6.5.2.1.1
Multiply 00 by -1−1.
0(38)+b=90(38)+b=9
Step 6.5.2.1.2
Multiply 00 by 3838.
0+b=90+b=9
0+b=90+b=9
Step 6.5.2.2
Add 00 and bb.
b=9b=9
b=9b=9
b=9b=9
b=9b=9
Step 7
Now that the values of mm (slope) and bb (y-intercept) are known, substitute them into y=mx+by=mx+b to find the equation of the line.
y=-38x+9y=−38x+9
Step 8