# Is y=x^2 + 2x-3 a quadratic?

Jun 22, 2015

Yes, it is a quadratic function

#### Explanation:

To find if a function (or equation) is a quadratic one you have to check if the function is a polinomial (it contains only of terms like $a {x}^{n}$ where $n \in \mathbb{N}$) and the highest power of $x$ is $2$.

Examples:

1) $y = 2 {x}^{2} - x + 7$ is a quadratic function
2) $y = - x + 7$ is not quadratic (no ${x}^{2}$)
3) $y = {x}^{2} + 7 x - \frac{2}{x}$ is not quadratic ($\frac{2}{x}$ is not a valid term in a polinomial)
4) $y = {x}^{4} - 2 {x}^{2} + 7$ is not quadratic (the highest power of $x$ is $4$ not $2$)