How do you solve x+y=7 and x-y=-3?

1 Answer
Oct 4, 2015

$x = 2$
$y = 5$

Explanation:

Given -
$x + y = 7$ ----------------(1)
$x - y = - 3$----------------(2)

Solve the first equation for $y$
y = 7-x#

Substitute this value in equation(2)

$x - \left(7 - x\right) = - 3$
$x - 7 + x = - 3$
$2 x = - 3 + 7$
$2 x = 4$
$x = \frac{4}{2} = 2$

Substitute $x = 2$ in equation (1)
$2 + y = 7$
$y = 7 - 2$
$y = 5$