How do you solve $- 2 x + y = 1$ $-2x + y = 1$ and $- 4 x + y = - 1$ $-4x + y = -1$ using substitution?

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How do you solve $- 2 x + y = 1$ $-2x + y = 1$ and $- 4 x + y = - 1$ $-4x + y = -1$ using substitution?

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Answer 1 · 2016-04-08T13:01:47

$(x, y) = (1, 3)$ $(x,y)=(color(cyan)(1,3))$

Explanation:

If
$XXX - 2 x + y = 1$ $color(white)("XXX")-2x+y=1$
then
$XXX y = 1 + 2 x$ $color(white)("XXX")color(red)(y)=color(blue)(1+2x)$

Since we are also told that
[3] $XXX - 4 x + y = - 1$ $color(white)("XXX")-4x+color(red)(y)=-1$
we can substitute $(1 + 2 x)$ $(color(blue)(1+2x))$ for $y$ $color(red)(y)$ to get
$XXX - 4 x + (1 + 2 x) = - 1$ $color(white)("XXX")-4x+(color(blue)(1+2x))=-1$

$XXX - 2 x + 1 = - 1$ $color(white)("XXX")-2x+1=-1$

$XXX x = 1$ $color(white)("XXX")color(green)(x)=color(brown)(1)$

Then substituting $(1)$ $(color(brown)(1))$ for $x$ $color(green)(x)$
in the original $- 2 x + y = 1$ $-2color(green)(x)+y=1$

$XXX - 2 \cdot (1) + y = 1$ $color(white)("XXX")-2*(color(brown)(1))+y=1$

$XXX - 2 + y = 1$ $color(white)("XXX")-2+y=1$

$XXX y = 3$ $color(white)("XXX")y=3$

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How do you solve $- 2 x + y = 1$ $-2x + y = 1$ and $- 4 x + y = - 1$ $-4x + y = -1$ using substitution?

1 Answer

Explanation:

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How do you solve −2x+y=1-2x + y = 1 and −4x+y=−1-4x + y = -1 using substitution?

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How do you solve $- 2 x + y = 1$ $-2x + y = 1$ and $- 4 x + y = - 1$ $-4x + y = -1$ using substitution?