Answer:
y - x = - 2 b
Step-by-step explanation:
Given-
3 x + 2 y = 5 a + b...................(i)
4 x - 3 y = a + 7 b.....................(ii)
Multiply by 3 and 2 in equation (i) & (ii) respectively-
Add equation (iii) & (iv)-
9 x + 6 y = 15 a + 3 a...................(iii)
8 x - 6 y = 2 a + 14 b ...................(iv)
17 x = 17 a + 17 b
x = a + b
Put x = a + b in equation (i)-
2 y = 5 a + b - 3 a - 3 b
2 y = 2 a - 2 b
y = a - b
∴ y - x = a - b - ( a + b )
y - x = a - b - a - b
y - x = - 2 b