2x + 3y = 12 Dan 3x-1y=7

2x+3y=12

3y=-2x+12

y=-2x/3+4

3x-1y=7

-1y=-3x+7

y=3x-7

2x+3y=12

3x-y=7

use subsituttion

make one of the equations equal to a placeholder

3x-y=7

subtract 7

3x-7-y=0

add y

3x-7=y

subsisute 3x-7 for y in first equation

2x+3 (3x-7) = 12

2x+9x-21=12

11x-21=12

add 21 to both sides

11x=33

divide both sides by 11

x=3

subsitute x for 3 in any equation

3x-7=y

3 (3) - 7=y

9-7=

2=y

x=3

y=2