Equation of a Line
Using Substitution to solve for a point of intersection
Solving word problems using linear systems
100

100- 12x + 4y - 3 = 17

A- y = -3x + 5

100

x+y=14  x-y=4

y=14-x

x-(14-x)=4    x-14+x=4    2x=14+4

2x=18  x=9

y=14-9   y=5

POI= (9,5)

100

The sum of Abdul’s and Josh’s ages is 36 Josh is 4 years younger than Abdul. How old are they?

x+(x+4)=36

Josh is 16

Abdul is 20

200

200- 12x - 6y + 37 = -11

A-  y = 2x + 8

200

3x-y=3   9x-3y=9

y=3x-3  9x-3(3x-3)=9

9x-9x+9=9

0x=0  y=-3

POI (0,-3)

200

Diljeet has 21.5 more Cardboard boxes  than Will in total they have 37.5 Cardboard boxes. How many Cardboard boxes  does Diljeet have? How many Cardboard boxes does Will have?

(x+21.5)+x=37.5

Diljeet has 29.5 cardboard boxes

Will has 8 cardboard boxes

300

y=-7x+3   y=-5x+5

-7x+3=-5x+5

-7x+5x=5-3   -2x=2   x=-1

y=-5(-1)+5

y=10

POI= (-1,10)

300

Ben is hiking and took 2 hours to travel 24 km down a steep hill.  The return trip (up the hill) took 3 hours.  What was the speed of the Ben? How much difference was the hill making to Ben's pace?


x=Bens hiking speed

y=The difference the hill is making to his speed

Ben took 2 hrs to travel 24 km at a specific speed while going down a hill.

x+y=12 km/h


Ben 3 hrs to travel 24 km at a specific speed while hiking up a hill.

x-y= 8 km/h


speed=10 km/h

Diffrence the hill made=2 km/h

400

-3x=-5y+7    2y=x-5

x=2y+5   -3(2y+5)=-5y+7

-6y+-15=-5y+7   -6y+5y= 7+15

-y=22   y=-22

x=2(-22)+5   x=-44=5  x=-39

POI (-39,-22)

400

Luch needs to make 10L of 42% bubbles for Mop bucket.The Soap solutions available are 30% soap and 50% soap. How many liters of each soap are needed to make the 42% soap?


30% soap=y


50% soap=x

He needs 10 L total

x+y=10L


30% soap and 50% soap combine to make 10L of 42% bubbles

0.3x+0.5y=4.2



Luch needs 6L of 50% soap and 4L of 30% soap

500

-x + 5x + 4y - 2y + 19 = 7

A: y = -2x - 6

500

2x+y=5   x-2y=-1

x=-1+2y    2(-1+2y)+y=5       -2+4y+y=5

-2+5y=5    5y=7  y=7/5 1.4

x=-1+2(7/5)   x=9/5  1.6

POI (9/5,7/5)

500

Jason invests his summer earnings of $3050. He invests part of the money at 8% per year and the rest at 7.5% per year. After one year these investments make $242 in simple interest. How much did he invest at each year?

x=8%

y=7.5%

He invests 3050 total

x + y=3050


He made $242 between his investments

0.08x+0.075y=242


Jason invested $400 into the 7.5% account and $2,650 into the 8% Account

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