Hello.
Multiply all terms by x and cancel:
x2x+1=18x
x3+1=18x(Simplify both sides of the equation)
x3+1−18x=18x−18x(Subtract 18x from both sides)
x3−18x+1=0
(Use cubic formula)
x=−4.27015,0.055565,4.214585
Check answers. (Plug them in to make sure they work.)
x=4.214585(Works in original equation)
x=−4.27015(Works in original equation)
x=0.055565(Works in original equation)
So the answer is: 4
Have a nice day