Writing Equations of Lines!

Given slope and a point

100

Slope = -3

Point = (9,2)

y=-3x+29

200

Slope = 8

Point = (6,2)

y=8x-46

300

m=2/5  and (-5,5)

y=2/5 x +7

400

m=1/3 and (3,-5)

y=1/3 x-6

500

m=1/2  and (-4,6)

y=1/2 x +8

What's my slope?

100

(12,8) and (4,3)

5/8

200

(7,9) and (13,5)

-2/3

300

(-2,6) and (4,7)

1/6

400

(0,4) and (0,7)

0

500

(-9,-7) and (7,-4)

3/16

Slope-Intercept Form from 2 points

100

(3, -5)  and (-7, 5)

y=-x-2

200

(6,-3) and (9, -2)

y=1/3 x-5

300

(-5,6) and (5,2)

y=-2/5 x +4

400

(3,-1) and (6,-1)

y=-1  or y=0x-1

500

(4,9) and (4,-1)

x=4

Point-Slope form to Slope-Intercept Form

100

y - 2=8(x-3)

y=8x-22

200

y +17=-3(x-1)

y=-3x-14

300

y-11=1/5(x-5)

y=1/5x+10

y=1/5x+10

400

y-2=1/6(x-3)

y=1/6x-2.5

500

y+3=-5(x+2)

y=-5x-13

Words

100

To earn some money, you will clean your neighbor's house.  You charge $11 per hour plus a $5 fee.  Write an equation to represent the situation.

y=11x+5

200

The cost of renting a jet ski is $40 per hour plus a $50 fee. What is the equation in Slope intercept form?

y=40x+50

300

Scott collects hats.  He has 65 hats and plans on buying 12 per year.  Write the equation in slope intercept form.

AND How many hats will he have in 3 years?

y=12x+65

101 hats

400

Sarah's car was worth $18,000 when she bought it.  Each year it's value drops $1500. Write the equation in Slope intercept form.

AND When will the car be worth $10,500?

y=-1500x+18000

7 years

500

Isaac had 83 pieces of candy.  He ate 5 pieces each day.  Write the situation in slope intercept form.

AND how many days will it take him to run out of candy?

y=-5x+83

17 days (16.6)