Determine whether the equation defines y as a function of x.
-$$x + y ^ { 2 } = 49$$
A) $y$ is a function of $x$
B) $y$ is not a function of $x$

Question

Quizplus · Accepted Answer

For a given value of $x$, there can be two values of $y$ (one positive and one negative) that satisfy the equation $x + y^2 = 49$, because when solving for $y$, we take the square root of both sides. This violates the definition of a function, which requires each input to have exactly one output.

Determine Whether the Equation Defines Y as a Function of X