Please help, this was on a past exam paper and i'm not sure how to go about it!

[Freddie1]

Which of the following functions are linear, support youranswersi)​

g(x) = x^2
​

h(x; y) = (0; x + y)​

p(x; y; z) = (x; y)

 

[HallsofIvy]

Do you not know the definition of "linear"?

A function of a singe variable, f(x), is linear if and only if f(ax+by)= af(x)+ bf(y) for any constants a and b. But it is easy to look at a function's formula and tell whether it is linear or not: anything other than f(x, y, z)= ax+ by+ cz+ d, for constants a, b, c, d for each component, is NOT linear- there can be no squares or higher powers or other functions.