Question

решите уравнение (x+5)(x-4)+x2+18 =0

Answer 1

$x^2+5x-4x-20+x^2+18=0$
$2x^2+x-2=0$
$D=1+4*2*2=17$
$x_{1,2}= frac{-1+/- sqrt{17} }{2*2}$