There is no LCM in this polynomial, unless it is -4x, which, in that case, the LCM would be x
Simplified: 
Restrictions: x CANNOT be 0 because then the denominator would become 0 and would not be possible
Okay. I’m no mathematician, but I’m pretty sure it would be 995/90 = h. I used the “/” as the divide symbol. This would be the equation because you need to divide the total by the cash per hour to be able to get the number of hours the plumber worked. I really hope this helps!