Question

x+y=12;x-y=5 solve don't cheating​

Answer 1

Step-by-step explanation:

substitutions method:-------------

$x + y = 12 \\ {eq}^{n} (1)$

$x - y = 5 \\ {eq}^{n} (2)$

from equation ( 1 ) :-----------

$x = 1 2- y \\ {eq}^{n} (3)$

put the value of x in equation ( 2 ) :----------

$x - y = 5 \\ 12 - y - y = 5 \\ - 2y = 5 - 12 \\ - 2y = - 7 \\ y = \frac{7}{2}$

from equation ( 3 ) :-------

$x = 12 - y \\ x = 12 - \frac{7}{2} \\ x = \frac{24 - 7}{2} \\ x= \frac{17}{2}$