Question

Which of the following represents a nonlinear function?

Answer 1

We know that all the functions of the form $y=mx+b$ are linear.

$y=3x-2$ is of the form $y=mx+b$, where $m=3$ and $b=-2$.
So, $y=3x-2$ represents a linear function.

$y=5$ is of the form $y=mx+b$, where $m=0$ and $b=5$.
So, $y=5$ represents a linear function.

$y=x^2$ cannot be represented in the form $y=mx+b$.
So, $y=x^2$ represents a nonlinear function.

$y=4x$ is of the form $y=mx+b$, where $m=4$ and $b=0$.
So, $y=4x$ represents a linear function.

Option C is correct.