2.4 “Writing Linear Equations”***When writing equations of lines, substitute values for:

y = mx + b

Given:1. Slope and y-intercept m = -3 b = 5

Step:1. Plug in values for “m” &

“b”.

Given: Point & Slope 2. (5, 4) m = -3

3. (-6, -2) m =

Steps:1. Plug in values for “x”, “y” &

“m” then solve for “b”.2. Use the given “m” and the

“b” just found and plug in to y = mx + b.

Given: Two Points4. (5, -2) (2, 10)

5. (4, -1) (-2, -13)

Steps:1. Use the slope formula to

find “m”. y2 – y1

x2 – x1

2. Use the slope and ONE point and plug in values to y = mx + b to solve for “b”.

Try These:6. m = -5 b = 7 7. (-6, 3) (6, 7)

Parallel & Perpendicular8. Find the equation of a line parallel to y = -4x + 1 that goes through the point (-2, 3).

Steps:1. Use the equation given to

find the slope “m”.2. Use the given point and

THE “m” you just found, then plug in to y = mx + b and solve for “b”.

3. Use the “m” & the “b” to write the equation.

Parallel & Perpendicular9. Find the equation of a line perpendicular to y = -3x + 2 that goes through the point (-9, 5).

Steps:1. Use the equation given to

find the slope “m”.2. Use the given point and

THE “m” you just found, then plug in to y = mx + b and solve for “b”.

3. Use the “m” & the “b” to write the equation.

Try These:10. Find the equation of a line perpendicular to y = x - 9 that goes through the point (8, -13).

11. Find the equation of a line parallel to y = 5x - 3 that goes through the point (0, 2).

Weird Ones12. Write the equation of a line that passes through the point (5, -1) and is parallel with y = 2.

13. Write the equation of a line that passes through the point (3, -4) and is perpendicular with x = -3.