Question

alguem sabe resolver esse sistema x+y=5 2x-y=7

Answer 1

x+y=5
2x-y=7


isola X
x=5 -y

2.5-y -y=7
10-2y=7
-2y= -10 +7
-2y= -3
2y=3
y= 3/2= 1,5


x+y=5
x+1,5=5
x= 5 -1,5
x= 3,5

Answer 2

x+y=5
2x-y=7
x=5-y
2(5-y)-y=7
10-2y-y=7
-3y=7-10
-3y=-3
y=1
x+1=5
x=5-1
x=4
S{(4,1)}