Can you use slope intercept form?

Section 4.7

• What do you know about slope-intercept form?

• Break down the phrase….

• A linear equation y = mx+b is written in slope-intercept form;

where m is the slope and

b is the y-intercept.

Slope – Intercept form…

-2x + y = -3

Find the slope and y-intercept…

First thing we do…

Get it into slope-intercept form.. y =

mx + bSecond thing we do… Pick out the

slope and the y-intercept

Y = 2x - 3 ? ?

Slope: 2 Y- intercept: -3

(1) Find the slope and y-intercept

(2)Plot the point (0,b) ; when b = -3(3) Use the slope to locate a second point on the line.

(4)Draw a line through the two points

3x + 4y = 8

What about this…

SLOPE?

Y-intercept?

7y – 14x = 28

You Try it…

What does it mean to be parallel?

• .

Parallel Lines…

Parallel bars?Parallel

parking?

• Parallel lines are DIFFERENT lines in the same plane that never intersect. If they have

the SAME SLOPE and different y-intercepts, they

are deemed as parallel.

• Any two vertical lines are parallel

The REAL Definition..

Line A: 3y = -9x – 5 Line B: 2y – 6x = -5 Line C: 12x + 4y = 1

How can you tell which lines are parallel…

(1) Rewrite each equation in slope-intercept form…

(2) Identify the slope of each equation (3) Compare the slopes;

• If they are have the same slope, then they are parallel..

Page 246#1,2,11-29(odd),49,

51, 53(15 problems)

Homework

Grab a board, a marker, and

an eraser

Get with a partner…

What is the equation for slope-intercept form…..

Find the slope and y-intercept of the

equation…

y = 2x + 1

Find the slope and y-intercept of the

equation…

y – x = 3

Rewrite the equation in slope-intercept form…

3x + y = -11

Rewrite the equation in slope intercept form…

3x – 6y = 18

Find the slope and y-intercept of this

equation….

3x + 4y = 16

Find the slope and y-intercept of this

equation….

X + y = 0

Determine if the two equations are parallel

lines…

line a: 2x – 12 = y

line b: y = 10 + 2x

What’s your wager?!?!

Challenge Question….

Determine which graphs of the equations are parallel lines….

LINE A: 3y – 4x = 3

LINE B: 3y = -4x + 9

LINE C: 16x -12y = 24