When you substitute P and Q you should get wrong equation, then it will have no solution. A) -68x-68=-68x+34 -68 = 34 False, no solutions
B)-68x+68=-68x+34 68=34 False, no solutions C)-68x-34=-68x+34 -34=34 False, no solutions D) -68x+34=-68x+34 34=34 True , so this equation will have infinite number of solution.
A,B,C have no solutions, D has infinite number of solutions.