Which equation is a quadratic equation?

A. y + 7 = −3x(4 − x) + 9x
B. y = −2x + 5
C. y + 2x3 = (2x − 2)(x + 5)
D. y − 9x = (x2 + 1)(5x − 1) + 3

Question

Which equation is a quadratic equation?
 	
A. y + 7 = −3x(4 − x) + 9x
B. y = −2x + 5
C. y + 2x3 = (2x − 2)(x + 5)
D. y − 9x = (x2 + 1)(5x − 1) + 3

anonymous · Answer

a

anonymous · Answer

A

anonymous · Answer

Pretty sure C is quadratic, as well.  B is linear, D is cubic.

directrix · Answer

A) y = 3x^2 -3x -7

anonymous · Answer

i thought so to but I think that's a 2x^3.  i did the same with d...

directrix · Answer

C is a cubic, not a quadratic.

anonymous · Answer

OK, I now see the exponent in the problem without carat ^.  Yes.  Cubic.

anonymous · Answer

asker, all you need to do is find the degree of the polynomial... if the degree is 2, it's a quadratic.