How do you solve the linear system using substitution $x = 16 - 4y$ and $3x + 4y = 8$ ?

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Answer 1 · 2015-06-05T08:49:52

$x = color(blue)(16 - 4y$ ......equation $(1)$

$3x + 4y = 8$ .........equation $(2)$

substituting equation $(1)$ in equation $(2)$
$3color(blue)((16-4y)) + 4y = 8$

$48 - 12y + 4y = 8$
$48 - 8y= 8$
$- 8y= 8-48 = -40$
$y=-40/-8$
$color(blue)(y=5$

substituting $color(blue)(y$ in equation $(1)$ to find $x$
$x =16 - 4y$
$x =16 - 4.5 = 16-20$
$color(blue)(x = -4$

the solution for the system of equations is
$color(blue)(x= -4 and y = 5$

How do you solve the linear system using substitution x = 16 - 4yx = 16 - 4y and 3x + 4y = 83x + 4y = 8?