1. Write equations of lines in point-slope form.
You wrote linear equations given either one point and the slope or two points. (Lesson 4–2)
Write equations of lines in point-slope form.
Write linear equations in different forms.
Then/Now

2. point-slope form
Vocabulary

3. Concept 1

4. Write and Graph an Equation in Point-Slope Form
Write the point-slope form of an equation for a line that passes through (–2, 0) with slope
Point-slope form
Example 1

5. Graph the equation Plot the point at (–2, 0).
Write and Graph an Equation in Point-Slope Form
Graph the equation
Plot the point at (–2, 0).
Use the slope to find another point on the line. Draw a line through the two points.
Answer:
Example 1

6. Write the point-slope form of an equation for a line that passes through (4, –3) with slope –2.B C D
Example 1

7. Concept 2

8. Writing an Equation in Standard Form
In standard form, the variables are on the left side of the equation. A, B, and C are all integers.
Example 2

9. Write y – 3 = 2(x + 4) in standard form.B C D
Example 2

10. Writing an Equation in Slope-Intercept Form
Example 3

11. Write 3x + 2y = 6 in slope-intercept form.A B C D
Example 3

12. A. GEOMETRY The figure shows trapezoid ABCD with bases AB and CD.
Point-Slope Form and Standard Form
A. GEOMETRY The figure shows trapezoid ABCD with bases AB and CD.
Write an equation in point-slope form for the line containing the side BC.
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Example 4

13. Step 1 Find the slope of BC.
Point-Slope Form and Standard Form
Step 1 Find the slope of BC.
Slope formula
(x1, y1) = (4, 3)
(x2, y2) = (6, –2)
Example 4

14. Step 2 You can use either point for (x1, y1) in the point-slope form.
Point-Slope Form and Standard Form
Step 2 You can use either point for (x1, y1) in the point-slope form.
Using (4, 3)
Using (6, –2)
y – y1 = m(x – x1)
y – y1 = m(x – x1)
Example 4

15. B. Write an equation in standard form for the same line.
Point-Slope Form and Standard Form
B. Write an equation in standard form for the same line.
Example 4

16. A. The figure shows right triangle ABC
A. The figure shows right triangle ABC. Write the point-slope form of the line containing the hypotenuse AB. A B C D
Example 4

17. B. The figure shows right triangle ABC
B. The figure shows right triangle ABC. Write the equation in standard form of the line containing the hypotenuse. A B C D
Example 4