Question

Resolva a equação abaixo usando a fórmula de Bhaskara:
x²-2(x+1)=-2x+7

Answer 1

$x^{2}-2\left(x+1 \right )=-2x+7\\ \\ x^{2}-2x-2=-2x+7\\ \\ x^{2}-2x+2x-2-7=0\\ \\ x^{2}-9=0\\ \\ \\ a=1,\;\;\;b=0,\;\;\;c=-9\\ \\ \\ \Delta=b^{2}-4ac\\ \\ \Delta=\left(0 \right )^{2}-4\cdot \left(1 \right )\cdot \left(-9 \right)\\ \\ \Delta=0+36\\ \\ \Delta=36\\ \\ \\ x=\dfrac{-b\pm\sqrt{\Delta}}{2a}\\ \\ x=\dfrac{-\left(0 \right )\pm\sqrt{36}}{2 \cdot \left(1 \right )}\\ \\ x=\dfrac{0 \pm 6}{2}\\ \\ x=\pm 3\\ \\ \boxed{ \begin{array}{rcl} x=3&\text{ ou }&x=-3 \end{array} }$