Solving systems using substitution

2) y = x + 8

y = - 4x - 12

4) y = 3x - 4

y = x - 4

Answer: Daddy oh yeah

2) x=-4 y=4 4) x=0 y=-4

Step-by-step explanation:

2) Step: Substitute x+8 for y in y=-4x-12:

y=-4x-12

x+8=-4x-12

x+8+4x=-4x-12+4x (Add 4x to both sides)

5x+8=-12

5x+8+-8=-12+-8 (Add - 8 to both sides)

5x=-20

5x / 5 = - 20 / 5 (Divide both sides by 5)

x=-4

Step: Substitute - 4 for x in y=x+8:

y=x+8

y=-4+8

y=4 (Simplify both sides of the equation)

Answer:

x=-4 and y=4

4) Step: Substitute 3x-4 for y in y=x-4:

y=x-4

3x-4=x-4

3x-4+-x=x-4+-x (Add - x to both sides)

2x-4=-4

2x-4+4=-4+4 (Add 4 to both sides)

2x=0

2x/2 = 0 / 2 (Divide both sides by 2)

x=0

Step: Substitute 0 for x in y=3x-4:

y=3x-4

y = (3) (0) - 4

y=-4 (Simplify both sides of the equation)

Answer:

x=0 and y=-4