Hi again............. I am glad to help you again.
6x + 35 + 9x = 15x(x+4) -25
6x + 35 + 9x = 15x² + 60x - 25
15x + 35 = 15x² + 60x - 25
Now, we gonna put all the common terms together
15x - 60x + 35 + 25 - 15x² =
-45x + 60 - 15x² = 0
Now, we need to factorize
-15(x-1)(x+4)=0
Set factors equal to 0
x -1 = 0 or x + 4 = 0
x = 1 or x = 4
I hope that's help !