Graphing Linear Equations

Use the point-slope formula y = m(x - h) + k to substitute the slope in for m and the point into (h, k). Then distribute and simplify.

Given a point and a slope, how do we write an equation of the line?

First, use the Slope formula to find the slope. Then, use the point-slope formula y = m(x - h) + k to substitute the slope in for m and the point into (h, k). Then distribute and simplify.

Given two points, how do we write and equation of the line?

y = m(x - h) + k where m is the slope and (h, k) is a point

Point-Slope Formula

y = mx + b where m is the slope and b is the y-intercept

Slope-Intercept Formula

y = #

The equation of a horizontal line is always:

x = #

The equation of a vertical line is always:

A vertical line that passes through 4 on the x axis.

The equation x = 4 is:

A horizontal line that passes through -2 on the y axis.

The equation y = -2 is:

zero

The slope of a horizontal line is always:

undefined

The slope of a vertical line is always:

Start at b (y-intercept) on the y-axis then use the m (slope) to rise and run.

To graph a line using slope-intercept form you must first solve for y then:

7

What is the slope in y = 7x + 4

2

What is the y intercept in y = 8x + 2

Solve the equation for y to get y = mx + b

When asked to graph a line using slope-intercept form, the first step is to:

Substitute in 0 for x and then 0 for y. Solve for the missing variable and then plot the points.

When asked to graph by plotting intercepts, we must: