Precalculus Examples
(-2,-8)(−2,−8) , m=13m=13
Step 1
Step 1.1
Use the formula for the equation of a line to find bb.
y=mx+by=mx+b
Step 1.2
Substitute the value of mm into the equation.
y=(13)x+by=(13)x+b
Step 1.3
Substitute the value of xx into the equation.
y=(13)⋅(-2)+by=(13)⋅(−2)+b
Step 1.4
Substitute the value of yy into the equation.
-8=(13)⋅(-2)+b−8=(13)⋅(−2)+b
Step 1.5
Find the value of bb.
Step 1.5.1
Rewrite the equation as 13⋅-2+b=-813⋅−2+b=−8.
13⋅-2+b=-813⋅−2+b=−8
Step 1.5.2
Simplify each term.
Step 1.5.2.1
Combine 1313 and -2−2.
-23+b=-8−23+b=−8
Step 1.5.2.2
Move the negative in front of the fraction.
-23+b=-8−23+b=−8
-23+b=-8−23+b=−8
Step 1.5.3
Move all terms not containing bb to the right side of the equation.
Step 1.5.3.1
Add 2323 to both sides of the equation.
b=-8+23b=−8+23
Step 1.5.3.2
To write -8−8 as a fraction with a common denominator, multiply by 3333.
b=-8⋅33+23b=−8⋅33+23
Step 1.5.3.3
Combine -8−8 and 3333.
b=-8⋅33+23b=−8⋅33+23
Step 1.5.3.4
Combine the numerators over the common denominator.
b=-8⋅3+23b=−8⋅3+23
Step 1.5.3.5
Simplify the numerator.
Step 1.5.3.5.1
Multiply -8−8 by 33.
b=-24+23b=−24+23
Step 1.5.3.5.2
Add -24−24 and 22.
b=-223b=−223
b=-223b=−223
Step 1.5.3.6
Move the negative in front of the fraction.
b=-223b=−223
b=-223b=−223
b=-223b=−223
b=-223b=−223
Step 2
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=13x-223y=13x−223
Step 3