Do all quadratic equations have two solutions?

I may only be in 8th grade but I am absolutely positive that all quadratic equations have 2 solutions.

No - They may have 0,1, or 2 answers

For example, the problem x^2 + 8x +16 = 0 has only one solution -4.

This is because the radical evaluates to 0 rendering the +/- sign irrelevant.