Enter a problem...
Algebra Examples
What is the equation of the line that passes through the point (−5,2) and has a slope of 45 ?
Step 1
Step 1.1
Use the formula for the equation of a line to find b.
y=mx+b
Step 1.2
Substitute the value of m into the equation.
y=(45)x+b
Step 1.3
Substitute the value of x into the equation.
y=(45)⋅(−5)+b
Step 1.4
Substitute the value of y into the equation.
2=(45)⋅(−5)+b
Step 1.5
Find the value of b.
Step 1.5.1
Rewrite the equation as 45⋅−5+b=2.
45⋅−5+b=2
Step 1.5.2
Simplify each term.
Step 1.5.2.1
Cancel the common factor of 5.
Step 1.5.2.1.1
Factor 5 out of −5.
45⋅(5(−1))+b=2
Step 1.5.2.1.2
Cancel the common factor.
45⋅(5⋅−1)+b=2
Step 1.5.2.1.3
Rewrite the expression.
4⋅−1+b=2
4⋅−1+b=2
Step 1.5.2.2
Multiply 4 by −1.
−4+b=2
−4+b=2
Step 1.5.3
Move all terms not containing b to the right side of the equation.
Step 1.5.3.1
Add 4 to both sides of the equation.
b=2+4
Step 1.5.3.2
Add 2 and 4.
b=6
b=6
b=6
b=6
Step 2
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=45x+6
Step 3