Question

What is the value of x+y for the equation? y=4x-5, and y=-4x+19

Answer 1

`x+y=10`

Explanation:

`y=4x-5`
`y=-4x+19`

From this we can say

`4x-5=y=-4x+19`

`4x-5=-4x+19`

Now add `5` to both sides of the equation:

`4x-5 \ ul(+5) =-4x+19 \ ul(+5)`

`4x=-4x+24`

Then add `4x` to both sides of the equation:

`4x \ ul(+4x) =-4x \ ul(+4x) +24`

`8x=24`

Now we can divide both sides of the equation by `8`, or you can say, that

`8x=24`

so

`x=24/8= 3`

Knowing the value of `x`, we can easily find the value of `y`.

`y=4x-5`

`4x-5=4*3-5=12-5=7`

So

`x=3 and y=7`

Therefore

`x+y=3+7=10`