Graph using Slope-Intercept Form

A linear equation in the form y=mx+b is written in slope-intercept form where m is the slope and b is the y-intercept of the equation’s graph.Ex. y = mx + b slope y-intercept

y = x + 1

1

3

3

1

SOLUTION

EXAMPLE 1 Identify slope and y-intercept

Identify the slope and y-intercept of the line with the given equation.

y = 3x + 41. 3x + y = 22.

The equation is in the form y = m x + b. So, the slopeof the line is 3, and the y-intercept is 4.

a.

b. Rewrite the equation in slope-intercept form by solving for y.

EXAMPLE 1 Identify slope and y-intercept

3x + y-3x

= 2 -3x

Write original equation.Subtract 3x from each side

y = – 3x + 2 Put your variable term first, remember to keep the sign with the coefficient.ANSWER

The line has a slope of – 3 and a y-intercept of 2.

SOLUTION

EXAMPLE 1 Identify slope and y-intercept

Identify the slope and y-intercept of the line with the given equation.

The equation is in the form y = mx + b.So, the slope

of the line is 5, and the y-intercept is –3.

y = 5x – 3 2. 3x – 3y = 12

1.

GUIDED PRACTICE for Example 1

EXAMPLE 1 Identify slope and y-intercept

ANSWER

The line has a slope of : 1 and a y-intercept of –4.

GUIDED PRACTICE for Example 1

SOLUTION

Rewrite the equation in slope-intercept form by solving for y.

2. 3x – 3y = 12 Write original equation.

Divide 3 by equation.3x – 12 3

= 3y 3

Rewrite original equation.

y 3x - 12=

3

y x – 4= Simplify.

EXAMPLE 1 Identify slope and y-intercept

Identify the slope and y-intercept of the line with the given equation.

x + 4y = 63.

GUIDED PRACTICE for Example 1

EXAMPLE 1 Identify slope and y-interceptGUIDED PRACTICE for Example 1

ANSWER

The line has a slope of and a y-intercept of 1 . 41–

2

1

SOLUTION

Rewrite the equation in slope-intercept form by solving for y.

x + 4y-x

= 6-x

Write original equation.

Divide equation by 4.4y = – x + 6

Rewrite original equation.Subtract x from each side.

Simplify.– x

4+

6

4y=

– x + 6=

4

y4