Question 574759
If all you have is the measures of 3 sides, given as (x+4), (x+3), and (x-1), there is no single solution. Infinite values of x such that x>2 would give you a possible triangle, and only one of those x values would make it a right triangle.
The more usual problem gives you the measures of the three angles. If the measures  of the three angles of a triangle, in degrees were (x+4), (x+3), and (x-1), knowing that they add up to 180 degrees, you would set up an equation and find x.
A more difficult and unusual problem would give you the measure of an angle, and the measures of the three sides as a function of x. That problem, while difficult, could be solved.