Equation of a straight line given one point and slope.

In this brief tutorial we will look closer at straight lines. We will be going over how to come up with the equations given certain information, this time using the slope of the line and a point it passes through to do this.

The idea of the straight line is one of the intuitive concepts of geometry. The straight line can be understood as an infinite set of points aligned in a single direction.

A line going through the point (X1,Y1) and having slope of 𝑚 would have the equation of a line typically written as (Y-Y1)=m(X-X1)

To solve equation of a straight line given one point and slope you will need to follow the steps ahead:

1. Find the slope. [ m= ¿? ]
2. Use point slope equation. [ ( Y-Y1)=m(X-X1) ]
3. Solve for Y.
4. Plot the equation

Example:

Given m=3 and the point (1,2)

1.Find the slope.

m = 3

2.Use point slope equation.

Point: (1,2)

X1 = 1, Y1 = 2

( Y-Y1)=m (X-X1)

change the values in the equation

(Y-2) = 3(X-1)

3.Solve for 𝖸.

(Y-2) = 3(X-1)

Y-2=3X-3

Y=3X-3+2

Y=3X-1

4. Plot the equation.

To plot the equation we just write it down in our app Quick Graph and you will see instantly the desired plot.

Plot using Quick Graph

If you want to practice your plots or learn more about graphing an equation use Quick Graph.

If you already have Quick Graph, press here to see this equation.