both y’s would automatically cancel so all you have left is 2x=10. divide 2 on each side and the 2s on the left cancel. 10/2=5 so x=5. then substitute the 5 into either equation (preferably x+y=4). then subtract 5 on each side and the 5s on the left again cancels out. so you have y=4-5 and y= -1. hope this helps you!!
