Answer:
See below.
Explanation:
The question is poorly formatted. I'll interpret, and answer, as per below.
when is y directly proportional to x?
(one answer)
a) y=x²
b) y=5x
c) every time x doubles y doubles
d) every time x increases by 1 y increases by 1
e) y=2x-3 y=12/x
a) y=x² No. Y goes by by a squared power
b) y=5x Yes. Y increases by a constant factor (5) per increase in x
c) every time x doubles y doubles Yes. Proportional increase.
d) every time x increases by 1 y increases by 1 Yes.
e) y=2x-3 Yes
f) y=12/x No. y decreases by 1/x