This is a simultaneous equation
1)2x+y=7
2)-8x+9y=9
1)*4 (so 2x becomes 8x so we can add or take to get rid of x)
1)8x+4y=28
2)-8x+9y=9
2) + 1)
13y=37
Y=2.846153846
To check the answer is correct find x
8x+(4*2.84...)=28
8x=28-11.384..
8x=16.615..
X=2.0769..
Input into 2)
(-8*2.07..)+(9*2.84..)=9
It is equal to 9
So y is correct
