How to Convert Slope Intercept Form to Standard Form

••• anyaberkut/iStock/GettyImages

Any equation that relates the first power of x to the first power of y produces a straight line on an x-y graph. The standard form of such an equation is Ax + By + C = 0 or Ax + By = C. When you rearrange this equation to get y by itself on the left side, it takes the form y = mx +b. This is called slope intercept form because m is equal to the slope of the line, and b is the value of y when x = 0, which makes it the y-intercept. Converting from slope intercept form to standard form takes little more than basic arithmetic.

TL;DR (Too Long; Didn't Read)

To convert from slope intercept form y = mx + b to standard form Ax + By + C = 0, let m = A/B, collect all terms on the left side of the equation and multiply by the denominator B to get rid of the fraction.

The General Procedure

An equation in slope intercept form has the basic structure

y = mx + b
    \begin{aligned} y - mx &= (mx - mx ) + b \\ y - mx &= b \end{aligned}
    \begin{aligned} y - mx - b &= b - b \\ y - mx - b &= 0 \end{aligned}
    -mx + y - b = 0

    If m is an integer, then B will equal 1.

    -\frac{A}{B}x + y - b = 0
    -Ax + By - Bb = 0
    -Ax + By - C = 0

Examples:

(1) - The equation of a line in slope intercept form is:

y = \frac{1}{2} x + 5

What is the equation in standard form?

    y - \frac{1}{2}x = 5
    y - \frac{1}{2}x - 5 = 0
    2y - x - 10 = 0
    -x + 2y - 10 = 0

    You can leave the equation like this, but if you prefer to make x positive, multiply both sides by -1:

    x - 2y + 10 = 0

    or

    x - 2y = -10

    (2) - The slope of a line is -3/7 and the y-intercept is 10. What is the equation of the line in standard form?

    The slope intercept form of the line is

    y = -\frac{3}{7}x + 10

    Following the procedure outlined above:

    \begin{aligned} y + \frac{3}{7}x - 10 = 0 \\ 7y + 3x - 70 = 0 \\ 3x + 7y -70 = 0 \\ \text{or} \\ 3x + 7y = 70 \end{aligned}

Related Articles

How to Find Slope From an Equation
How to Find the X Intercept of a Function
How to Determine if an Equation Is an Identity?
Standard Form of a Line
When Solving Quadratic Equations, What Questions Should...
How to Write Linear Equations in Algebra
How to Write a Repeating Decimal As a Fraction
How to Write "Three Tenths" in Standard Form
How to Reset a TI89
What Are Reciprocal Identities?
How to Figure Out the Slope of a Line
To Calculate Arcsine, What Buttons Do You Press on...
What is the Identity Property of Multiplication?
How to Find the Minimum or Maximum in a Quadratic Equation
How to Turn a Negative Denominator into a Positive
How to Simplify Algebraic Expressions
How to Use a Calculator for Trigonometry
How to Interpret Linear Equations
How to Cancel a Natural Log
How to Solve a Parabola