When the sum of an unknown number z and twenty two is divided by the same unknown number, the quotient is twelve what is the unknown number

The unknown number . . . . .  (z)

The sum of the unknown number and 22 . . . . .  (z + 22)

The sum of the unknown number and 22
divided by the same unknown number . . . . . . .  (z + 22) / z

You said that quotient is 12.              (z + 22) / z  =  12

Multiply each side by 'z' :                  (z + 22)       =  12 z

Subtract 'z' from each side:                      22        =  11 z

Divide each side by  11 :                           2         =      z .