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Pearson Algebra 1 Common Core, 2011

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Pearson Algebra 1 Common Core, 2011 View details

3. Slope-Intercept Form

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Exercise 52 Page 313

What information can you learn from the slope-intercept form of an equation?

Practice makes perfect

Equations written in slope-intercept form follow a specific format. y= mx+ b In this form, m represents the slope of the line and b represents the y-intercept.

Identifying the Slope and y-intercept

Since the given equation is not in slope-intercept form, let's rewrite it so that it will be easier to identify the slope and y-intercept.

4x+3y=2x-1

LHS-4x=RHS-4x

3y=- 2x-1

▼

.LHS /3.=.RHS /3.

.LHS /3.=.RHS /3.

y=- 2x-1/3

Write as a difference of fractions

y=- 2x/3-1/3

MoveNegNumToFrac

Put minus sign in front of fraction

y=-2x/3-1/3

MovePartNumRight

a* b/c=a/c* b

y=-2/3x-1/3

Below we highlight the slope m and y-intercept b. y= -2/3x - 1/3 ⇔ y= -2/3x+( -1/3) The slope is - 23. The y-intercept is - 13, so the graph crosses the y-axis at the point (0, - 13).

Graphing the Equation

A slope of - 23 means that for every 3 units we move in the positive horizontal direction, we move 2 units in the negative vertical direction. m= -2/3 ⇔ rise/run=- 2/3 To graph the equation, plot the y-intercept and then use the slope to find another point on the line.

Graph of a Linear Equation

Subchapter links

Lesson Check p.311

Practice and Problem-Solving Exercises p.312-314

Standardized Test Prep p.314

Mixed Review p.314