Question

10. 2x + 7y = 1
2x - 4y = 12
Solve for y

Answer 1

The solution for y = -1.

Explanation:

Given:

`2x\ +\ 7y\ =\ 1` ....(1)

`2x\ -\ 4y\ =\ 12` ....(2)

So, to solve for y, first we solve for x in equation (2):

`2x-4y=12`

⇒
`2x=12+4y`

Dividing both sides by 2,

⇒
`x=6+2y`

Now, substituting the value of x in equation (1):

`2x+7y=1`

⇒
`2(6+2y)+7y=1`

⇒
`12+4y+7y=1`

⇒
`12+11y=1`

⇒
`11y=1-12`

⇒
`11y=-11`

Dividing both sides by 11,

⇒
`y=-1`

Therefore, the solution for y = -1.