I think that first one represents a function.
Answer:
f(x)=-3x+4
(can't see some of your choices)
Step-by-step explanation:
We want x to be independent means we want to write it so when we plug in numbers we can just choose what we want to plug in for x but y's value will depend on our choosing of x.
So we need to solve for y.
9x+3y=12
Subtract 9x on both sides
3y=-9x+12
Divide both sides by 3:
y=-3x+4
Replace y with f(x).
f(x)=-3x+4
