Answer:
9 x + 8 y = 10 (I)
y = -4x + 7 (II)
One way is to rewrite the second as
4x + y = 7
Now multiply this equation by 8
32 x + 8 y = 56
9 x + 8 y = 10 and now subtract the equations
23 x = 46 this gives x as 2
From equation (II) y = -4 (2) + 7 = -1
So our values are (2, -1)
Check:
(I) 9 x + 8 y = 10 9 * 2 - 8 = 10
(II) 4 x + y = 7 or 4 * 2 - 1 = 7
Or you can substitute equation (II) directly into equation (I)
