Question

what is the value of 81x2y3+z if x=3 y=4 and z=19

Answer 1

Ok first of all I am assuming you mean
 
81.(x**2).(y**3) +z = Value

We just need to simply substitute x , y and z

81.(3*3)(4*4*4) +19 = Value

46656 + 19 = Value..............>> Value = 46675