Question

resolva a equação do 2° grau completa: x²-7x+12=0

Answer 1

$\Large\boxed{\begin{array}{l}\sf x^2-7x+12=0\\\sf\Delta=b^2-4ac\\\sf\Delta=(-7)^2-4\cdot1\cdot12\\\sf\Delta=49-48\\\sf\Delta=1\\\sf x=\dfrac{-b\pm\sqrt{\Delta}}{2a}\\\\\sf x=\dfrac{-(-7)\pm\sqrt{1}}{2\cdot1}\\\\\sf x=\dfrac{7\pm1}{2}\begin{cases}\sf x_1=\dfrac{7+1}{2}=\dfrac{8}{2}=4\\\\\sf x_2=\dfrac{7-1}{2}=\dfrac{6}{2}=3\end{cases}\end{array}}$