You can put this solution on YOUR website! Let the number be 'n'
3 times the number increased by 5= 3*n +5 = say x
77 decreased by 9 times the number= 77- 9*n = x
Equating both the equations
3n +5 = 77- 9n
we will bring the term with the variable together
3n + 9n= 77-5
12n = 72
n= 72/12
n= 6