Bellwork

You will need a graphing calculator today!!

linear NOT linear

y-intercept: y-coordinate ofthe point where a line crossesthe y-axis.

y-intercept = 4

slope= -3 8

http://www.phschool.com/atschool/academy123/html/bbapplet_wl-problem-431001.html

y = mx + b slope y-

intercepthttp://www.phschool.com/atschool/academy123/html/bbapplet_wl-problem-430899.html

Homeworkpp 294-297

2, 6, 10, 22, 23,

32, 35, 41, 45, 47,

50, 52, 56, 57, 62-64

Bellwork

point-slope form- non-vertical line that passes through point (x ,y ) with slope m

1 1

y - y = m ( x - x )

1 1

y - y = m ( x - x )

1 1

http://www.phschool.com/atschool/academy123/html/bbapplet_wl-problem-431007.html

http://www.phschool.com/atschool/academy123/html/bbapplet_wl-problem-431009.html

http://www.phschool.com/atschool/academy123/html/bbapplet_wl-problem-431010.html

Homework

y = mx + b

Slope-Intercept Form

Slope is easy to find.

What is the slope of x = ?What is the slope of y = ?

VUXHOY

STANDARD FORM Transform Standard Form

into Slope-Intercept Form:

Step 1 Ax + By = C

Step 2 By = -Ax + C

Step 3 y = -Ax + C B B

y = -Ax = C B B

What's the slope?m = -A

B

Example 1: Parallel Lines Parallel lines have exactly the same slope.

Equation of red line: y = 1x + 3 2 2Equation of blue line: y = 1x - 1 2

All horizontal lines are parallel and have a slope of what?

HOY

All vertical lines are parallel and have a slope of what?VUX

No matter what form of equation you use, find the slope and you have the slope of all the parallel line.

I will give you an equation and a point.

Find the slope of the equation.

That's all you need the equation for; you are finished with it.

Plug the slope and point into the the point-slope form of the equation.

Example 2: Perpendicular Lines·Form right angles where they meet·Slopes are negative, or opposite, reciprocals·Product of perpendicular = -1

Examples of negative reciprocals

1 and -3 1 and -1 3 1

-1 and 2 2 1

I will give you an equation and a point.

Find the slope of the equation.

That's all you need the equation for; you are finished with it.

Find the negative reciprocal of the slope.

- 1 5

Plug the slope into the slope-intercept formto write the equation.

Homework pp 314 -317

32-50 even

57-59

70