2x+7y=24 /*-1 2x+7y=24
2x+9y=28 2x+7*2=24
2x=24-14
-2x-7y=-24 2x=10 /:2
2x+9y=28 + x=5
---------------------
2y=4 /:2
y=2 x=5
y=2
2x+7y=24 /*-1 2x+7y=24
2x+9y=28 2x+7*2=24
2x=24-14
-2x-7y=-24 2x=10 /:2
2x+9y=28 + x=5
---------------------
2y=4 /:2
y=2 x=5
y=2