Question

Which equation is a quadratic equation?

Answer 1

y + 7 = -3x(4 - x) + 9x
y = -2x + 5
y + 2x3 = (2x - 2)(x + 5)
y - 9x = (x2 + 1)(5x - 1) + 3

Answer 2

y + 7 = -3x(4 - x) + 9x
If you multiply it out, you have x^2, which means a quadratic.