Substitution Practice

When they tell you what x or y is (Situation 1)

40

x + y = 6

y = 5

(1, 5)

100

3x + y = 10

y= 4

(2,4)

200

-5x + 2y = 25

x = 3

(3, 20)

300

-2y -4x = 30

x = 2

(2, -19)

500

- 9x --2y = 12

x = 2

(2, -15)

When y= an expression (Situation 2)

40

y = 6x − 11 

−2x − 3y = −7

(2, 1)

100

2x − 3y = −1

 y = x − 1

(4,3)

200

y = −3x + 5 

5x − 4y = −3

(1,2)

300

y = 5x − 7 

−3x − 2y = −12

(2,3)

500

y = −2x +9

5x − 2y = 18

(4,1)

When they are both y= (Situation 3)

40

y = x + 8 

y = 3x + 18

(-5, 3)

100

y = 6x + 10 

y = -8x - 18

(-2,-2)

200

 y = -5x + 11

 y = 4x + 2

(1,6)

300

y = 3x - 8 

y = 2x - 7

(1,-5)

500

y = -x - 6

y = x - 4

(-1, -5)

Grab Bag

40

y = -3x +4

y = -5x - 16

(-10, 34)

100

y = 5x - 5 

5x + 3y = -15

(0, -5)

200

x = 5

2x -6y = 16

(5, -1)

300

-4x - 4y = 4

 y = -5x + 19

(5, -6)

500

y = 2x - 1

y = 5x - 4

(1, 1)