2х+4х=30

(2+4)*х=30

6х=30

х=30/6

х=5

4у+2у-у=20

у*(4+2-1)=20

5у=20

у=20/5

у=4

7у+у-2у=24

у*(7+1-2)=24

6*у=24

у=24/6

у=4

2х+4х=30

6х=30

х=30/6

x=5

4y+2y-y=20

5y=20

y=20/5

y=4

7y+y-2y=24

6y=24

y=24/6

y=4