Question

8x +12y= 1/5 and 6+8y=1/7 then x/y equals to
1) 4
2)3
3) 1/2
4)2​

Answer 1

8x + 12y = 1/5 __(eq.1) × 3

6x + 8y = 1/7 __(eq.2) × 4

multiply eq.1 with 3 and eq.2 with 4 we get

24x + 36y = 3/5

24x + 32y = 4/7

_(-)__(-)____(-)___

4y = 3/5 - 4/7

=> 4y = (21 - 20)/35

=> y = 1/35 × 1/4

=> y = 1/140

put this value in eq.1

8x + 12y = 1/5

=> 8x + 12/140 = 1/5

=> 8x = 1/5 - 3/35

=> 8x = (7-3)/35

=> 8x = 4/35

=> x = 4/(35×8)

=> x = 1/70

so,

x/y = (1/70)/(1/140). = (140/70) = 2 (ans.)