Question

Which equation is a quadratic equation?
Need help on this...
y = −4(3x + 2)

y + 3x3 = (x − 2)(3x + 8)

y − 3 = (2x2 + 11)(x − 1) + 3x

y + 5x = −2x(4 − x) + 1

Answer 1

@Hero can you give me some help on this one? Or a step by step guide?

Answer 2

If I had a nickel for everytime I saw this question. It's like everyone is taking the same online course.

Answer 3

^ Haha I'm actually doing it to get an A. I got a B and it took me off the Principles list of all A's and my parents weren't to thrilled.

Answer 4

You have to start by putting each function in y=mx+b format. Do you know how to do that?

Answer 5

Yes :D thank you

Answer 6

Forgot all about Slope Intercept Form

Answer 7

So basically a quadratic is doing to have a squared x in the function. So which of the choices do you have an x^2 once y is isolated?

Answer 8

It's "A" right...?

Answer 9

A isn't going to have an x^2 because there is only one x in the problem. After distribution it will be y=-12x-8

Answer 10

Putting things in slope intercept form is not required here. The only thing you need to know to solve this the simplified form of one of those equations needs to be a quadratic

Answer 11

Okay.

Answer 12

It is not possible to put quadratics or cubics in slope-intercept form

Answer 13

No it doesn't have to b in slope intercept form, but y still has to be by itself and the problem because much easier to analyze when it is put in that form.

Answer 14

A true quadratic function is ax^2+bx+c=0

Answer 15

that is where the plug-ins for the quadratic formula come from. Am I wrong?

Answer 16

Yes, you want to isolate y in each equation. Interestingly enough, there's still an even easier way to do it.