I MAY BE WRONG but I don't think there is a solution to this problem.
-1/2 does not equal -9/10
accordng to principles of multiplication multiplying both sides by the same non zero number won't change the solution set. I don't believe there is a number you can multiply both sides by to make those equal to each other.
its like saying 2=3 there is just no way you can solve that. you can multiply both sides by any number and it still won't be equal ( has to be the same number you multiply 2 by that you multiply 3 by).
now if it was -1/2x=-9/10 it would be a different story.
Happy new years.