Question

Solve the simultaneous equations. You must show all your working to find x and y. 1/2x -3y = 9 5x y + y = 28

Answer 1

the answer to the question is x=6 and y=-2

Answer 2

The right question is:

`(1)/(2)x - 3y = 9`

`5x + y = 28`

Answer:

`x = 6`

`y = -2`

Explanation:

Given

`(1)/(2)x - 3y = 9`

`5x + y = 28`

Required

Solve for x and y

Make y the subject of formula in the second equation

`y = 28 - 5x`

Substitute
`y = 28 - 5x` in the first equation

`(1)/(2)x - 3(28 - 5x) = 9`

Open the bracket

`(1)/(2)x - 3*28 - 3*- 5x = 9`

`(1)/(2)x - 84 + 15x = 9`

Collect Like Terms

`(1)/(2)x + 15x = 9+ 84`

`(x)/(2) + 15x = 9+ 84`

`(x+30x)/(2) = 93`

`(31x)/(2) = 93`

Multiply both sides by 2

`2 * (31x)/(2) = 93 * 2`

`31x = 186`

Divide both sides by 31

`(31x)/(31) = (186)/(31)`

`x = (186)/(31)`

`x = 6`

Recall that
`y = 28 - 5x`

So;

`y = 28 - 5 * 6`

`y = 28 - 30`

`y = -2`

Hence;

`x = 6` and
`y = -2`