IMAT 2020 Question 54

guys here i dont understand how she did the highlighted part i dont understand how she went from X^2… TO X^2 +2(5/4)x…)

and if you have another way for solving this, pls mention it.

In first step she’s taken 2 commonly out …then in second step she writes 2 5/4 which basically means 5/2 when u solve it . And 5/4 is written two times which cancels out each other as signs are opposite…she has done these steps for easiness…hope it helps …