Question

2 x+y=10 2×-y=6 -2×+y=12 2x+y=10 x-y=5 x+y=3

Answer 1

Boa tarde

a) 

2x + y = 10
2x - y = 6 

4x = 16
x = 4
8 + y = 10
y = 2
S = (4, 2) 

b)

-2x + y = 12,
2x + y = 10

2y = 22
y = 11
-2x + 11 = 12
2x = -1
x = -1/2 
1 + y = 12
y = 11 

d)

x - y = 5
x + y = 3

2x = 8
x = 4
4 - y = 5
y = 4 - 5 = -1