How do you solve $y=3x$ and $x+y=8$ using substitution?

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Answer 1 · 2016-04-06T12:30:47

The solution for the system of equations is:
$color (green)(x=2)$

$color(green)(y =6)$

$color(green)(y= 3 x$ ...............equation $(1)$
$x + y = 8$ ........equation $(2)$

Substituting equation $1$ in $2 :$

$x + y = 8$

$x + color(green)(3 x) = 8$

$4x = 8$

$x = 8 /4 = 2$

$color (green)(x=2)$

Substituting the value of $x$ in equation $1$ to find $y$ :
$y= 3 x$

$y= 3 * color(green)(2)$

$color(green)(y =6)$

How do you solve y=3xy=3x and x+y=8x+y=8 using substitution?