Finite Math Examples
(5,4)(5,4) , (-9,7)(−9,7)
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=7-(4)-9-(5)m=7−(4)−9−(5)
Step 5
Step 5.1
Simplify the numerator.
Step 5.1.1
Multiply -1−1 by 44.
m=7-4-9-(5)m=7−4−9−(5)
Step 5.1.2
Subtract 44 from 77.
m=3-9-(5)m=3−9−(5)
m=3-9-(5)m=3−9−(5)
Step 5.2
Simplify the denominator.
Step 5.2.1
Multiply -1−1 by 55.
m=3-9-5m=3−9−5
Step 5.2.2
Subtract 55 from -9−9.
m=3-14m=3−14
m=3-14m=3−14
Step 5.3
Move the negative in front of the fraction.
m=-314m=−314
m=-314m=−314
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=(-314)⋅x+by=(−314)⋅x+b
Step 6.3
Substitute the value of xx into the equation.
y=(-314)⋅(5)+by=(−314)⋅(5)+b
Step 6.4
Substitute the value of yy into the equation.
4=(-314)⋅(5)+b4=(−314)⋅(5)+b
Step 6.5
Find the value of bb.
Step 6.5.1
Rewrite the equation as -314⋅5+b=4−314⋅5+b=4.
-314⋅5+b=4−314⋅5+b=4
Step 6.5.2
Simplify each term.
Step 6.5.2.1
Multiply -314⋅5−314⋅5.
Step 6.5.2.1.1
Multiply 55 by -1−1.
-5(314)+b=4−5(314)+b=4
Step 6.5.2.1.2
Combine -5−5 and 314314.
-5⋅314+b=4−5⋅314+b=4
Step 6.5.2.1.3
Multiply -5−5 by 33.
-1514+b=4−1514+b=4
-1514+b=4
Step 6.5.2.2
Move the negative in front of the fraction.
-1514+b=4
-1514+b=4
Step 6.5.3
Move all terms not containing b to the right side of the equation.
Step 6.5.3.1
Add 1514 to both sides of the equation.
b=4+1514
Step 6.5.3.2
To write 4 as a fraction with a common denominator, multiply by 1414.
b=4⋅1414+1514
Step 6.5.3.3
Combine 4 and 1414.
b=4⋅1414+1514
Step 6.5.3.4
Combine the numerators over the common denominator.
b=4⋅14+1514
Step 6.5.3.5
Simplify the numerator.
Step 6.5.3.5.1
Multiply 4 by 14.
b=56+1514
Step 6.5.3.5.2
Add 56 and 15.
b=7114
b=7114
b=7114
b=7114
b=7114
Step 7
Now that the values of m (slope) and b (y-intercept) are known, substitute them into y=mx+b to find the equation of the line.
y=-314x+7114
Step 8