1. Perfect square trinomials, are 2nd degree polynomials, of the form 
so that 
, which can be written as perfect squares.
2. For example
3. Thus
are perfect square trinomials.
4.
5. In the first case -b=20, so b=-20. In the second case, -b=-20, so b=20.
6. b∈{-20, 20}
2. For example
3. Thus
4.
5. In the first case -b=20, so b=-20. In the second case, -b=-20, so b=20.
6. b∈{-20, 20}