Chapter Summary and Review continued
5.2
Examples on
pp. 278–280
Point-Slope Form
EXAMPLE
Write in slope-intercept form the equation of the line that passes through
(5, 2) and that has slope 3.
y y1 m(x x1)
Write the point-slope form.
Substitute 3 for m, 5 for x1 and 2 for y1.
y (2) 3(x 5)
y 2 3x 15
Use the distributive property and simplify.
y 3x 13
Subtract 2 from each side.
Write the equation of the line in point-slope form. Then write the
equation in slope-intercept form.
10.
11.
y
3
(1, 4)
12.
y
3
1
1
1
y
1 x
3 x
1
(3, 1)
1
1
(2, 0)
1
x
13. Write the equation of the line that is parallel to the line y 5x 2 and
passes through the point (2, 3).
5.3
Writing Linear Equations Given Two Points
EXAMPLE
Examples on
pp. 285–287
Write the equation of the line that passes through the points (5, 4) and (2, 2).
Find the slope.
y y
x2 x1
2
1
m
2 (4)
25
Write the formula for slope
24
3
6
3
2
Substitute (5, 4) for (x1, y1) and (2, 2) for (x2, y2);
then simplify.
Write the equation, using point-slope form. Use m 2 and (x1, y1) (5, 4).
y y1 m(x x1)
y (4) 2(x 5)
y 4 2x 10
y 2x 6
314
Chapter 5
Writing Linear Equations
Write point-slope form.
Substitute 2 for m, 5 for x1, and 4 for y1.
Simplify and use distributive property.
Subtract 4 from each side.