A quadratic in standard form is a perfect square trinomial set equal to 0. How many solutions has it?

1. A perfect square trinomial factors as a single bracket squared. 2. Running the quadratic formula on such an equation makes the expression under the square root simplify to 0. 3. Adding 0 and subtracting 0 give the same value, so both branches of the formula land on one number. 4. So an equation of that shape has just one solution, which is what a discriminant of 0 always signals. _Source: OpenStax Intermediate Algebra (CC BY 4.0), section 9.3 Solve Quadratic Equations Using the Quadratic Formula_