Question

Which equation is a quadratic equation?

y + 3 = 5x + 10

y + 4x2 = (4x − 2)(x + 3)

y − 8x = (x2 + 1)(9x − 7)

y = 2x + 7x(x + 1)

Answer 1

wow really?
last one is for sure

Answer 2

ok :) thats what i thought too but i cant trust myself anymore

Answer 3

\[y = 2x + 7x(x + 1) \]
\[y=2x+7x^2+7x\]
\[y=7x^2+9x\] quadratic means degree is 2

Answer 4

okay :) thanks :)

Answer 5

yw