How do you solve by substitution $x + 7y = 33$ and $3x - 2y = 7$ ?

Question

2436 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2015-06-07T12:00:13

$x + 7y = 33$

$x = color(red)(33 - 7y$ .......equation $(1)$
$3x - 2y = 7$ ........equation $(2)$

Substituting equation $(1)$ in $(2)$ to find $y$

$3color(red)((33 - 7y)) - 2y = 7$

$99 - 21y- 2y = 7$
$-23y= 7-99$
$-23y= -92$
$color(blue)(y= 4$

Substituting $y$ in equation $(1)$ to find $x$
$x =33 - 7y$

$x =33 - 7.4 = 33 - 28$
$color(blue)(x =5$

The solution for the system of equations is:
$color(blue)( x = 5 , y=4$

How do you solve by substitution x + 7y = 33x + 7y = 33 and 3x - 2y = 73x - 2y = 7?