Question

Identify which equation is a quadratic equation.
Answer
y = -6x - 3
y + x2 = (x - 1)(x + 7)
y - 9 = (x - 1)(x2 + 4)
y = 5x(x + 3) - 8

Answer 1

Look for the one in which the highest power of x is 2.

Answer 2

You can eliminate the first one as it is a linear, and no variable to the second power.

Answer 3

The second one has a x^2 but it goes away leaving no x^2.

Answer 4

Now you are left with just two, and I bet you can take Mertsj advise and select the correct one.

Answer 5

THE 3RD ONE? (:

Answer 6

I am looking at the third one Haleybob, and I see an x^3 not an x^2. Look at it again and remember the hint that Mertsj gave you.

Answer 7

4th one? lolol

Answer 8

Note that (x-1)(x^2 +4)= x^3+4x-x^2 -4

Answer 9

Yes, you got it, Just remember a quadratic will have a variable to the 2nd power but not a larger power like say a 3, which would be a cubic equation.