Question

Y^2 − x^2 = 100 is that a function or no?

Answer 1

Answer:

No, it is not an equation

Step-by-step explanation:

See attached graph:

Answer 2

No. If you solve it for $y$, you have

$y=\pm\sqrt{x^2+100}$

So, given a certain value for $x$, say $x=0$, you have

$y=\pm\sqrt{100}=\pm10$

So, you're associating two y-values for each x value. This implies that this is not a function.