How do I substitut 3x+y=2, 4×+y=20?

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How do I substitut 3x+y=2, 4×+y=20?

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Answer 1 · 2018-02-24T02:22:20

$(x, y) = (18, - 52)$ $(x,y)=(18, -52)$

Explanation:

$3 x + y = 2$ $3x+y=2$ => $y = 2 - 3 x$ $y=2-3x$
$4 x + y = 20$ $4x+y=20$
$4 x + 2 - 3 x = 20$ $4x+2-3x=20$
$x = 18$ $x=18$
$y = 2 - 54 = - 52$ $y=2-54=-52$
$(x, y) = (18, - 52)$ $(x,y)=(18, -52)$

Answer 2 · 2018-02-24T02:25:26

$y = - 52$ $y=-52$
$x = 18$ $x=18$

Explanation:

Since $y$ $y$ is a constant in both equations, you can shift $3 x$ $3x$ in $3 x + y = 2$ $3x+y=2$ , so $y = 2 - 3 x$ $y=2-3x$ .
Then you can just substitute into $4 x + y = 20$ $4x+y=20$
So $4 x + (2 - 3 x) = 20$ $4x+(2-3x)=20$
$x + 2 = 20$ $x+2=20$
$x = 18$ $x=18$
Then substitute into any equation $x = 18$ $x=18$
Substituting into first equation,
$y = 2 - 3 (18)$ $y=2-3(18)$
$y = - 52$ $y=-52$

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How do I substitut 3x+y=2, 4×+y=20?

2 Answers

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