More math work?

Question

Given the values of x and y, find an equation of variation in which y varies directly as x.
y=15, when x=12

Answer 1

this question should tAKE YOU 10 SECONDS TO SOLVE.
having seen the other answers, I feel compelled to answer cause they are wrong. Direct variation means y = kx, where k is to be determined. We know that y=15 when x = 12, hence k = 15/12 = 5/4
the equation is y = (5/4)x
EDIT:
it seems that some people here do not know the meaning of direct variation. YOU DO HAVE ENOUGH INFORMATION TO SOLVE THIS QUESTION. IN A DIRECT VARIATION BETWEEN Y AND X, (0,0) IS A POINT ON THE LINE AND TWO POINTS DETERMINE ONE AND ONLY ONE LINE.
ONLY ONE OTHER PERSON HAS THIS RIGHT.

Answer 2

y=x+3

Answer 3

y=x+3

Answer 4

I am going to assume there is a linear relationship that is being sought.

This means

y = mx + b

since when y = 15, x = 12

15 = 12m + b

if we assume m = 1 (we have no justification to assume this but let's do it anyway)

15 = 12 + b, then b = 3 and

y = x + 3

If we assume m = 10 (also no justification to do so)

15 = 10x12 +b
15= 120 + b
-105 = b
and
y = 10 x - 105

All of this shows that

1. we don't have enough info to solve this if it is linear
2. we don't even have sufficient info to say the relationship is linear

Answer 5

This is conceptually a wrong question, as with just one value of x and y you can form infinite number of relations between them. Theoretically, to form one UNIQUE relation between x and y, you need infinite relationships, but that's not practically possible, so there're methods like interpolation and extrapolation to find a possible relation, which matches with the ideal relation at least at the values given.
Here, say, i'll give you two possible solutions:
one: y=x+3
two: y=2x-9
etc..

Answer 6

variation means that you should deduct the smaller number from the larger one... so since x is equivalent to 12 and y is equivalent to 15, the variation is 3..
so as to say...
y=15
x=12
y-x=(a)
15-12=3
y=x+3

you can twist it around... its a linear equation

Answer 7

That sounds like an obfuscated way of saying y = x + 3.

Answer 8

y=kx
DY=kDX, y=15,x=12
k=5/4
DY=5/4DX.