Answer: it would be 1
Step-by-step explanation: The factorial is defined only for natural numbers and 0, and it grows faster than any polynomial. This means that, if we check all natural values for x, we’ll either find the solution, or reach a point where x!>x2, after which there can be no solutions.
Let’s try it:
If x=0, x2=0 and x!=1
If x=1, x2=x!=1 - our solution!
Just to make sure there are no more solutions, let’s keep checking until x!>x2:
If x=2, x2=4 and x!=2
If x=3, x2=9 and x!=6
If x=4, x2=16 and x!=24
Now, 24>16, so looking further is pointless. The only solution is x=1