Question

What is the answer of this -x+3y=20 7y=x

Answer 1

The answer of -x+3y=20; 7y=x will be x = -
`(7)/(2\\)` and y = -
`(1)/(2)`.

Given,

-x+3y=20 .... (1)

7y=x .... (2)

By using the method of substitution.

We will use equation (2) as

7y=x

=>y=
`(x)/(7)` ....(3)

Putting equation (3) in (1)

We have, -x+3(
`(x)/(7)`)=20

Taking L.CM.

`(-7x+3x)/(7)` = 20

-7x +3x = 140

-4x = 140

0r, x = -
`(140)/(4)`

x = -
`(7)/(2)`

Now by putting value of x in equation (2), we get

7y = x

7y = -
`(7)/(2)`

0r, y = -
`(1)/(2)`

Thus, x = -
`(7)/(2\\)` and y = -
`(1)/(2)`