x2+6x−13=0x^{2}+6 x-13=0x2+6x−13=0
x2+5x−4=0x^{2}+5 x-4=0x2+5x−4=0
x2−5x−4=0x^{2}-5 x-4=0x2−5x−4=0
x2−6x+13=0x^{2}-6 x+13=0x2−6x+13=0