49x2−56x−15=049 x^{2}-56 x-15=049x2−56x−15=0
49x2−56x+15=049 x^{2}-56 x+15=049x2−56x+15=0
49x2−14x−15=049 x^{2}-14 x-15=049x2−14x−15=0
49x2−14x+15=049 x^{2}-14 x+15=049x2−14x+15=0
