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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 50 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

The given equation is not written in slope-intercept form. Let's isolate the y-variable to rewrite the equation in this format.

3y+6=- 2x

LHS-6=RHS-6

3y=- 2x-6

▼

.LHS /3.=.RHS /3.

.LHS /3.=.RHS /3.

y=- 2x-6/3

Write as a difference of fractions

y=- 2x/3-6/3

Calculate quotient

y=- 2x/3-2

MovePartNumRight

a* b/c=a/c* b

y=- 2/3x-2

MoveNegNumToFrac

Put minus sign in front of fraction

y=-2/3x-2

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

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