Are the following systems of linear equations? Why or why not?

1.) y=2x+15

2x-4y=12

2.) 2x-2y=12

3z-4x=18

all are linear eqns since they follow the formula y = mx + c

1) y = 2x + 15

2) 2x - 4y = 12 can be rewritten as ...

4y = 2x - 12 = " y = 1/2 x - 3

3) 2x - 2y = 12 can be rewritten as ...

2y = 2x - 12 = " y = x - 6

4) 3z - 4x = 18 can b rewritten as ...

3z = 4x - 18 = " z = 4/3 x - 6