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

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Answer 1 · 2018-04-28T02:03:58

$x + y = 10$ $x+y=10$

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

From this we can say

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

$4 x - 5 = - 4 x + 19$ $4x-5=-4x+19$

Now add $5$ $5$ 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

$x+y=3+7=10$