Answer:
x=0
y=-21/7
Step-by-step explanation:
Let the two unknown be x and y
x+y=-7...(1)
x-y=14...(2)
From (1) make x the subject of formula
x=-7-y...(3)
Substitute (3) into (2)
-7-y-y=14
-7-2y=14
Add 7 to both sides
-2y=21
Add both sides by-2
y=-21/2
Substitute the value of y into (3)
x=-7-(-21/2)
x=-7+21/3
Lcm
x=-21+21/3
x=0/3
x=0
