Question

×2-12×+8=0 equação do 2°grau

Answer 1

$\large\boxed{\begin{array}{l}\rm x^2-12x+8=0\\\begin{cases}\rm a=1\\\rm b=-12\\\rm c=8\end{cases}\\\rm\Delta=b^2-4ac\\\rm\Delta=(-12)^2-4\cdot1\cdot8\\\rm\Delta=144-32\\\rm\Delta=112\\\rm x=\dfrac{-b\pm\sqrt{\Delta}}{2a}\\\\\rm x=\dfrac{-(-12)\pm\sqrt{112}}{2\cdot1}\\\\\rm x=\dfrac{12\pm4\sqrt{7}}{2}\begin{cases}\rm x_1=\dfrac{12+4\sqrt{7}}{2}=6+2\sqrt{7}\\\\\rm x_2=\dfrac{12-4\sqrt{7}}{2}=6-2\sqrt{7}\end{cases}\\\\\rm S=\{6-2\sqrt{7},6+2\sqrt{7}\}\end{array}}$