How do I know if a quadratic equation will have one, two, or no solutions

Answer 1

examine the discriminant

http://www.mathnstuff.com/math/spoken/here/2class/320/quadequ.htm

Answer 2

p=2a+2b solve for b
b=p-2a/2b

Answer 3

-5/7y -1/2y times 2/3 - 1/21y i do not know the steps

Answer 4

How to solve common monomial factor?
like this ex:

1.) x2y+x2y2=x2y

2.) 2a+2b

3.) 3b-9b2-12a