x2−2x−5=0x^{2}-2 x-5=0x2−2x−5=0
x2+2x−5=0x^{2}+2 x-5=0x2+2x−5=0
x2−2x+5=0x^{2}-2 x+5=0x2−2x+5=0
x2+2x+5=0x^{2}+2 x+5=0x2+2x+5=0