[9.01] Which equation is a quadratic equation?

3x − y = 8x + 2

y = 7x(5 − 2x) + 9

7x2 + y = (3 + x)(7x − 1)

y − 3 = (x2 − 3)(8x + 3)

Question

[9.01] Which equation is a quadratic equation?

 3x − y = 8x + 2

 y = 7x(5 − 2x) + 9

 7x2 + y = (3 + x)(7x − 1)

 y − 3 = (x2 − 3)(8x + 3)

anonymous · Answer

The third. When you expand it, you see it has a degree of 2

anonymous · Answer

degree?

anonymous · Answer

Ah yes haha sorry, when you have a polinomial, the degree is the number of the biggest exponent. So since for example $x+1=x^1+1$, the degree of $x+1$ is 1. Something like $x^2+2x-4$ would have a degree of two. Or for example, something like $x^9-x^7+x^2-16$ has a degree of nine