# Which one of these is quadratic? A) `y=x^2+3x` B) `f(x) = x (4-x)-3` C) `3x^2-2=5x`

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A quadratic equation in x is an equation that can be written in the general form:

`ax^2+bx+c=0`

where, a, b and c are real numbers with ‘a’ having a non-zero value.

A quadratic equation is also defined as a univariate polynomial equation of the second degree.

Options A) and B) contains equations that are not univariate, hence these two do not represent quadratic equations.

The equation in option C) is `3x^2-2=5x`

Which can be rewritten as:

`3x^2-5x-2=0`

This is definitely a quadratic equation, in x.

**Thus, the correct answer is option C).**

**Sources:**

c. because it has an a,b and c

c.

A quadratic is essentially ax^2+bx+c.

And, only choice C has those characteristics.