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Five-Minute Check (over Lesson 2–3) CCSS Then/Now New Vocabulary Key Concept: Slope-Intercept Form Example 1: Write an Equation in Slope-Intercept Form Key Concept: Point-Slope Form Example 2: Write an Equation Given Slope and One Point Example 3: Standardized Test Example Key Concept: Parallel and Perpendicular Lines Example 4: Write an Equation of a Perpendicular Line Lesson Menu

Find the rate of change for the data. A. –22 mi/gal B. mi/gal C. mi/gal D. 22 mi/gal 5-Minute Check 1

Find the slope of the line that passes through points (2. 3, 9 Find the slope of the line that passes through points (2.3, 9.5) and (3.8, 20). A. –7 B. C. 7 D. 5-Minute Check 2

Find the slope of the line that passes through points (3, 5) and (–6, 5). B. 0 C. 1 D. 3 5-Minute Check 3

Determine the rate of change of the graph. B. C. D. 3 5-Minute Check 4

Mathematical Practices 2 Reason abstractly and quantitatively. Content Standards A.SSE.1.b Interpret complicated expressions by viewing one or more of their parts as a single entity. A.CED.2 Create equations in two or more variables to represent relationships between quantities; graph equations on coordinate axes with labels and scales. Mathematical Practices 2 Reason abstractly and quantitatively. CCSS

You determined slopes of lines. Write an equation of a line given the slope and a point on the line. Write an equation of a line parallel or perpendicular to a given line. Then/Now

slope-intercept form point-slope form parallel perpendicular Vocabulary

Concept 1

• Write an equation in slope-intercept form for the line. Step 1 Find the slope. Slope formula (x1, y1) = (–1, 4), (x2, y2) = (2, 3) Simplify. Example 1

Step 2 Use the slope and a point to find the y-intercept. Write an Equation in Slope-Intercept Form Step 2 Use the slope and a point to find the y-intercept. Slope-intercept form Simplify. The y-intercept is Example 1

Step 3 Substitute the values into the slope-intercept equation. Write an Equation in Slope-Intercept Form Step 3 Substitute the values into the slope-intercept equation. Slope-intercept form Example 1

Write an equation in slope-intercept form for the line. B. C. D. Example 1

Concept 2

Point-slope form Simplify. Write an Equation Given Slope and One Point Example 2

Subtract 2 from each side. Write an Equation Given Slope and One Point Subtract 2 from each side. Answer: Example 2

A. B. C. D. Example 2

What is an equation of the line through (2, –3) and (–3, 7)? B C D Read the Test Item You are given the coordinates of two points on the line. Example 3

Step 1 Find the slope of the line. Solve the Test Item Step 1 Find the slope of the line. Slope formula (x1, y1) = (2, –3), (x2,y2) = (–3, 7) Simplify. The slope is –2. That eliminates choices B and C. Example 3

Step 2 Write an equation. Use either ordered pair for (x1, y1). Point-slope form m = –2; (x1, y1) = (2, –3) Simplify. Subtract 3 from each side. Answer: D Example 3

Which is an equation of the line that passes through (2, 5) and (–1, 3)? B. C. D. Example 3

Concept

Write an Equation of a Perpendicular Line Write an equation in slope-intercept form for the line that passes through (3, –2) and is perpendicular to the line whose equation is y = –5x + 1. Example 4

Distributive Property Write an Equation of a Perpendicular Line Point-slope form Distributive Property Subtract 2 from each side. Answer: Example 4

A. B. C. D. Example 4

End of the Lesson

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