Question

me ajudem
a)
{ x+y=7
{x-y=3
b)
{2x+ y=5
{x-2y=5

Answer 1

X+3=2

X-7>10

7+8<18

5+3=9

Answer 2

x+y=7  ===> x = 7 - y ==> x= 7-2 ==> x=5

x-y=3  ===> 7-y -y =3 ==> -2y=-7 + 3 ==> -2y= -4 ==> y=2

2x+ y=5  ==> 2( 5 + 2y) + y = 5 => 10 + 4y +y =5 => 5y= -5 => y= - 1

x-2y=5 => x= 5+ 2y ==> x= 5 + 2(-1) ==> x = 5 -2=> x=3