Warm UpGraph : y = 3.5Graph: x = ­5

What is the slope? What is the slope?

HW Solutions Prac 2­3 # 17­51 odd

Writing Equations of Lines

Need 2 things: slope and y­intercept

Example:

1. Write the equation of a line that has a slope of 5 and a y-intercept of - 6.

Steps (using y = mx + b)

1. Find m

2. Find b

3. Write the equation.

2. Write the equation of a line that has a slope of 3 and goes through the point ( 2, 8).

3. Write the equation of a line that has a slope of 3/4 and goes through the point ( 8, - 2).

Note: slope formula

m =

4. Write the equation of a line going through the points (3, 5) and ( - 1, 9).

5. Write the equation of the line containing the points ( 8, 3) and ( 4, 5 ).

6. Write the equation of the line containing the points ( 3, ­ 1) and ( 2, ­ 3 ).

Writing Equations of

Parallel and Perpendicular Lines

Write the equation of the line that goes through the point ( - 3, - 5) and is parallel to the line y = - 2x + 3.

Graph both lines.

Through ( - 4, 1) ; parallel to y = 3/4x - 5

Through (2, - 2) ;perpendicular to y = -2x - 4 Graph both lines.

Through (4, - 3);perpendicular to y = 4/5x + 1

HW # 23 Worksheet # 1-14

** Quick Quiz Thursday

Parallel lines, Perpendicular lines, slopes, slope formula, equations of lines