Answer:
ii
Explanation:
from what you've written in the comments I think this question requires you to find the equation that can be expressed in two variables,so the best way to do this is to solve the pairs as simultaneous equations and see the ones that will give you two answers x and y
if you solve the first pair you will have
x + y = 5
2x+2y=10
2(x + y =5)
1(2x+2y=10)
2x+2y=10
2x+2y=10--
now from this you will see that it cannot be expressed as two variables because the answer is just zero..
for the second equation it can be expressed as two variables
x - y = 8
3x-3y =16
3(x-y =8)
1(x-3y=16)
3x-3y=24
x - 3y=16
2x/2=8/2
x=4
x-y=8
4-y=8
-y=8-4
-y/-1=4/-1
y=-4...
so you see it can be expressed as two variables..
if you solve the third one it will also give you an answer which is zero so it can't be expressed as two variables.
and the fourth one also cannot.
I hope this helps and if you don't understand feel free to ask..and sorry if it's wrong