Linear Equations (in Slope-Intercept Form)
(KS3, Year 8)

The Lesson

A linear equation is an equation that represents a line. A linear equation can be written in the form:

y equals m x plus c On a graph, a linear equation looks like a line:

line on a graph

Interactive Widget

You can use this interactive widget to create a graph of your linear equation. Use the buttons to change the values of the linear equation.
Change the Equation
y
x
y-intercept

A Real Example of a Linear Equation in Slope-Intercept Form

An example of a linear equation in slope-intercept form is given below:

y equals 2 x plus 1 If we compare this equation to y = mx + c, we can find the slope and y-intercept.

Other Forms of Linear Equations

There are other forms of linear equation.

Understanding What a Linear Equation Is...

Let's see what parts a linear equation can have:

What makes a linear equations A linear equation can contain:

...And What It Isn't

Now let's see what a linear equation cannot have. If you see any of these, it isn't a linear equation.

What does not make a linear equation The variables in the linear equation (the y and x) cannot contain:
  • Exponents - variables can only appear as x and y, not as x2 or y3
  • Roots - variables cannot appear as √x or ∛y
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See Also

What is a linear equation? What is the slope? What is the y-intercept? Finding the slope from a linear equation Finding the y-intercept from a linear equation