Not true, your variables were eliminated, so there is no solution.
Since this was listed under pythagorean theorem, it's possible that you were just supposed to determine if the triangle was a right triangle. If you set this up right, it's not.
Another possibility is that you have your hypotenuse on the wrog side of the = sign. , it doesn't matter which legs you pick for a and b, but you have to pick the hypotenuse for c. The hypotenuse is the side opposite the right angle that is usually signalled with a box in the corner. If c=1, this is solvable:
You can ignore the negative value in this case because you can't have a negative side of a triangle.