Question

Which expression gives the x-coordinate of the solution of the system?

{5x+3y= -18
{2x- 4y= -28}

Answer 1

To find the the expression that gives the value of
`x` we are going to proceed as follows:

`5x+3y=-18` equation (1)

`2x-4y=-28` equation (1)

Step 1. solve for
`y` in equation (2)

`2x-4y=-28`

`-4y=-28-2x`

`y= (-28-2x)/(-4)`

`y=7+ (1)/(2) x` equation (3)

Step 3. Replace equation (3) in equation (1) and solve for
`x`

`5x+3y=-18`

`5x+3(7+ (1)/(2) x)=-18`

`5x+21+ (3)/(2) x=-18`

`(13)/(2) x=-39`

`x= (-39(2))/((13))`

`x=-6`

We can conclude that the expression that gives the value of
`x` is:
`x=-6`