Solution - Simplification or other simple results

Step  1  :

Equation at the end of step  1  :

  90x -  (2•5x2)

Step  2  :

Step  3  :

Pulling out like terms :

 3.1     Pull out like factors :

   90x - 10x²  =   -10x • (x - 9) 

Final result :

  -10x • (x - 9)