Substitution Practice

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

100

x + y = 6

y = 5

(1, 5)

200

3x + y = 10

y= 4

(2,4)

300

-5x + 2y = 25

x = 3

(3, 20)

400

-2y -4x = 30

x = 2

(2, -19)

500

- 9x - 2y = 12

x = 2

(2, -15)

When y= an expression (Situation 2)

100

y = 6x 

−2x + y = -4

(-1, -6)

200

2x + y = −4

 y = x − 1

(-1, -2)

300

y = −3x + 5 

5x − 4y = −3

(1,2)

400

y = 5x − 7 

−3x − 2y = −12

(2,3)

500

y = −2x +9

5x − 2y = 18

(4,1)

When they are both y= (Situation 3)

100

y = 3x - 8

y = 2x - 7

(1, -5)

200

y = 6x + 10 

y = -8x - 18

(-2,-2)

300

 y = -5x + 11

 y = 4x + 2

(1,6)

400

y = x+8

y = 3x + 18

(-5, 3)

500

y = -x - 6

y = x - 4

(-1, -5)

Grab Bag

100

x = 5

2x - 6y = 16

(5, -1)

200

y = 5x - 5 

5x + 3y = -15

(0, -5)

300

y = -3x + 4

y = -5x - 16

(-10, 34) 

400

-4x - 4y = 4

 y = -5x + 19

(5, -6)

500

y = 2x - 1

y = 5x - 4

(1, 1)