How to find the slope of the line that passes through the pair of points

Olivia uses the work below to determine 55% of 720 which explains the error in olivia’s solution

Which of the following represents a number squared is equal to twenty more than nine times that number ? a) x squared = 9x + 20 b) x squared = 20x + 9 c) x squared > 9 + 20x d) x squared = 9 + x + 20

For how answer my question this will be the last question can you answer in math subject