Homework Help

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

user profile pic

babylove12 | Student, Grade 10 | (Level 3) eNoter

Posted June 30, 2013 at 4:32 PM via web

dislike 3 like

Which one of these is quadratic?

A) `y=x^2+3x`

B)  `f(x) = x (4-x)-3`

C) `3x^2-2=5x`

4 Answers | Add Yours

user profile pic

llltkl | College Teacher | (Level 3) Valedictorian

Posted June 30, 2013 at 4:51 PM (Answer #1)

dislike 1 like

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


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:


This is definitely a quadratic equation, in x.

Thus, the correct answer is option C).


user profile pic

atyourservice | Student, Grade 11 | TA | (Level 3) Valedictorian

Posted March 22, 2014 at 5:27 PM (Answer #2)

dislike 0 like

c. because it has an a,b and c

user profile pic

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

Posted July 31, 2014 at 11:21 AM (Answer #3)

dislike 0 like


user profile pic

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

Posted August 16, 2014 at 12:06 AM (Answer #4)

dislike 0 like

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

And, only choice C has those characteristics. 

Join to answer this question

Join a community of thousands of dedicated teachers and students.

Join eNotes