Respuesta :

Answer:

        A) {2 +√11 , 2 - √11}

Step-by-step explanation:

[tex]x^2 - 4x-7=0\\\\\underline{x^2 - 2\cdot x\cdot2+2^2}-2^2-7 =0\\\\\big(x-2\big)^2-4-7=0\\\\ \big(x-2\big)^2=11\\\\ x-2=\pm\sqrt{11}\\\\ x=2\pm\sqrt{11}[/tex]