Substitution Method (math) HELP!?

Question

I have no idea how to do these. I have the answer sheet but it doesn't have any explanation..Here are the 3 problems I need help with.

Directions: Solve each system of equation using the Substitution Method.

1) 2x - 2y + 6 = 0

3x = 4y - 1

2) 4x + 2y - (1/3) = 0

3y= - 4x + (7/6)

3) 4x - 3y = (3/2)

2x + 3y = 3

Answer 1

PROBLEM 1:

2x - 2y + 6 = 0

3x = 4y - 1

x = (4y - 1)/3

2x - 2y + 6 = 0

2((4y - 1)/3) - 2y + 6 = 0

(2(4y - 1))/3 - 2y + 6 = 0

(8y - 2)/3 - 2y + 6 = 0

8/3y - 2/3 - 2y + 6 = 0

2/3y - 2/3 + 6 = 0

2/3y + 16/3 = 0

2/3y = -16/3

y = -8

x = ((4y - 1)/3)

x = (4(-8) - 1)/3

x = (-32 - 1)/3

x = -33/3

x = -11

(-11, -8) = Final Answer

PROBLEM 2:

4x + 2y - (1/3) = 0

3y= - 4x + (7/6)

y= (- 4x + (7/6))/3

4x + 2y - (1/3) = 0

4x + 2((- 4x + (7/6))/3) - (1/3) = 0

4x + (2(- 4x + (7/6))/3) - (1/3) = 0

4x + (-8x + (7/3))/3) - (1/3) = 0

4x + -8/3x + 7/9 - 1/3 = 0

4/3x + 7/9 - 1/3 = 0

4/3x + 4/9 = 0

4/3x = -4/9

x = -1/3

y= (- 4x + (7/6))/3

y = (- 4(-1/3) + (7/6))/3

y = (4/3 + 7/6)/3

y = (5/2)/3

y = 5/6

(-1/3, 5/6) = Final Answer

PROBLEM 3:

4x - 3y = (3/2)

2x + 3y = 3

2x = 3 - 3y

x = (3 - 3y)/2

4x - 3y = (3/2)

4((3 - 3y)/2) - 3y = 3/2

(12 - 12y)/2 - 3y = 3/2

6 - 6y - 3y = 3/2

6 - 9y = 3/2

-9y = -9/2

y = 1/2

x = (3 - 3y)/2

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

x = (3 - 3/2)/2

x = (3/2)/2

x = 3/4

(3/4, 1/2) = Final Answer

Answer 2

x - y + 3 = 0

x = -3 + y

3(-3 +y) = 4y - 1

-9 +3y = 4y - 1

-9 + 1 = 4y - 3y

-8 = y

3x = 4(-8) - 1

3x = -32 - 1

3x = -33

x = -11

Answer 3

2(4/3y - 1/3) - 2y + 6 = 0

8y -2 - 6y + 18 = 0

2y = -16

y = -8

3x = -32 -1

x = -11

Answer 4

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