subtract x^2 from both sides of this equation to get:
6y = 4 - x^2
divide both sides of this eqaution by 6 to get:
y = (4 - x^2) / 6
offhand i would say yes because there is only one value of y for each and every value of x.
for example, assume that x = 2.
y = (4-4) / 6 which is equal to 0.
assume that x = -2.
y = (4-4) / 6 which is equal to 0.
you have the same value of y for two different values of x, but you don't have the same value of x for two different values of y, therefore y is a function of x.
the graph will show this to be true.
that graph is shown below:
give the graph the vertical line test and you will see that there is only one value of y for each and every value of x.
