Question

x 2 + x = 2
qual a resolução?

Answer 1

$x^{2} +x=2 \\ \\ x^2+x-2=0 \\ \\ a=1 \\ b=1 \\ c=-2 \\ \\ \Delta=b^2-4ac \\ \Delta=1^2-4(1)(-2) \\ \Delta=1+8 \\ \Delta=9 \\ \\ x= \frac{-b\pm \sqrt{\Delta}}{2a} = \frac{-1\pm \sqrt{9}}{2} = \frac{-1\pm3}{2} \\ \\ x'= \frac{-1+3}{2} = \frac{2}{2}=1 \\ \\ x"= \frac{-1-3}{2} = \frac{-4}{2}=-2 \\ \\ S=\{-2,1\}$