Question

x^2+42x-400=0
me ajudem é pra amanhã, se puder cálculo completo

Answer 1

$x^2+42x-400=0\\ \\ a=1\ b=42\ c=-400\\ \\ \Delta=b^2-4ac\\ \\ \Delta=42^2-4(-400)(1)\\ \\ \Delta=1764+1600\\ \\ \Delta=3364\\ \\ x=\frac{-b\pm\sqrt{\Delta}}{2a}\\ \\ x=\frac{-42\pm58}{2}\\ \\ \boxed{x=\frac{-42+58}{2}=\frac{16}{2}=8}\\ \\ ou\\ \\ \boxed{x= \frac{-42-58}{2}=\frac{-100}{2}=-50}$