Which equation is a quadratic equation?

Question

anonymous · Answer

The one in the form of $$y = ax^2 + bx + c$$ Where 'a' and 'b' are the respective coefficients

anonymous · Answer

Be careful, if the equation isn't in standard form you could have something like:

y = x(x + 2) - 5 which is also a quadratic equation.

shane_b · Answer

That's the general form of it....but it's any second degree polynomial equation.

anonymous · Answer

these are the answers 

y + 3 = 5x + 10 

 y + 4x2 = (4x − 2)(x + 3) 

 y − 8x = (x2 + 1)(9x − 7) 

 y = 2x + 7x(x + 1)

shane_b · Answer

Looking at the above replies, which one(s) do you think it is?

shane_b · Answer

That is, which one can be placed in the form:$$\large y=ax^2+bx+c$$?

anonymous · Answer

the first one ?

anonymous · Answer

You have to combine all of the terms on one side together to see which one matches the form. Have you done that?

shane_b · Answer

The first one doesn't even have a squared term :)

anonymous · Answer

idk whcih one it is ?

anonymous · Answer

is it the second one ?

shane_b · Answer

The second one is:
$$y + 4x^2 = (4x − 2)(x + 3) $$which simplifies to 
$$y=10x-6$$So that's not it...

anonymous · Answer

the last one ?

shane_b · Answer

You had a 50/50 chances and you got it right :)  

The last one can be simplified down to:$$y=7x^2+9x+0$$which is a quadratic equation in standard form.

shane_b · Answer

Do you understand how it was simplified to that?

anonymous · Answer

yess thankyouu

shane_b · Answer

ok, good luck!