If PQ+RS=PS and RS=XY, then PQ+XY=PS

Me with this one question, and i'll upvote the brainliest answer

What is the difference between the predicted value and the actual value

Me solve this problem, and someone clearly explain to me how to solve it.1.) use the value of the discriminant to determine if the given trinomials has 2 real solutions, 1 real solution, or no real solutions.a.  x2  − 4x  − 7 = 0b. 4r2  + 11r  − 3 = 0c. 3m2  + 7 = 0d.  t2  + 2t  + 1 = 0