Answer:
Step-by-step explanation:
5
x + y = 5 => x = 5 - y
y - 4 = - x
=> y - 4 = - ( 5 - y)
=> y - 4 = - 5 + y
=>4 = 5 , not true
So, no solution => system is inconsistent
6
option b
Explanation just as above.
