Question: how to find the zeros of a function with two variables?
Answer: Consider the following function: f(x) = x2 - 4. To find the zeroes of this function, you start the same way and set the function equal to zero. This gives you 0 = x2 - 4. Add 4 to both sides to isolate the variable, which gives you 4 = x2 (or x2 = 4 if you prefer to write in standard form).