 x^{2} +8x+12=0\\\Delta= b^{2} -4.a.c= \Delta= 8^{2} -4.1.12= \Delta=64-48=16 &nbsp;x1=-+8 \sqrt{16} /2=-8-4/2=-12/2=-6 &nbsp;x2=-+8 \sqrt{16} /2=-8+4=-4/2=-2&amp;#10;