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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llltkl | College Teacher | (Level 3) Valedictorian

Posted on

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:
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taangerine | Student, Grade 12 | (Level 1) Valedictorian

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

And, only choice C has those characteristics. 

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givingiswinning | Student, Grade 10 | (Level 1) Valedictorian

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c. 

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