Question

Resolva :
a) X-Y=3
4X+Y=-3

b)2x+7=7
5x-2y=-5

c) -x -y =-1
2x+y=3

Answer 1

a) 5x=0.
x=0/5.
x=0

4x+y=-3
4×0+y=-3
0+y= -3
y=-3
(0,-3)

c) x=2

-x-y=-1
-(-2)-y=-1
+2-y=-1
-y= -1-2
-y=-3
y=+3
(2,3)