Question

resolva os sistemas

x+y=8
x-y=-2


5x+y=8
x-y=10

Answer 1

x + x + y - y = 8 - 2
2x = 6
x = 3
y = 8 - 3
y = 5


5 x + x + y - y = 10 + 8
6 x = 18
x = 3
3 - y = 10
- y = 7
y = - 7

Answer 2

{x+y=8 ====> y=8-x
{x-y=-2
---------- (+)
2x = 6
x = 3 ✓ =====> y=8-3= 5 ✓


{5x+y=8 ====> y=8 -5x
{1x-y=10
----------- (+)
6x = 18
x = 3 ✓ =====> y=8 -5(3)= 8 -15= -7 ✓