No, it's not. A quadratic form is something like
[tex] ax^2+bx+c=0 [/tex]
They won't necessarily come in this exact form, but the important part is that there must be a constant term, and the other two terms must be powers of the variable, and one must be the square of the other.
In this case, for example, [tex] x^2 [/tex] is the square of [tex] x [/tex]
So, for example, an equation like
[tex] -7x^8-5x^4+18 [/tex] is in quadratic form, because there is a constant term (18), and [tex] x^8[/tex] is the square of [tex] x^4 [/tex]. You can tell this because the exponents are one the double of the other.
So, in this case, you have [tex] x^9 [/tex] which is the cube of [tex] x^3 [/tex], so this equation is not in quadratic form.
