Question

A) {x+y=3
{3x-y=5
B){y+x=7
{x-7=1

Answer 1

$\left \{ {{x+y=3} \atop {3x-y=5}} \right. \\\\x+y =3\\x=3-y\\ \\ 3x - y =5\\3(3-y) - y = 5\\9 - 3y - y = 5\\-3y - y=5+9\\-4y=14\\y=\frac{-14}{4} \\y = \frac{-7}{2} \\ \\ x = 3 - y\\ x=3-(\frac{-7}{2} )\\x=\frac{6+7}{2} \\x=-\frac{13}{2}$