akhunovaaliyap6akzm По теореме Виета: x1+x2=-7, x1•x2=-2, найдём
x1/x2 + x2/x1 = [(x1)^2 + (x2)^2]/[x1•x2] =
=[ (x1)^2 + 2x1•x2 + (x2)^2 - 2x1•x2]/[x1•x2]=
=[ (x1+x2)^2 - 2x1•x2 ] / [x1•x2]=
=[ (-7)^2 - 2 (-2) ] / [-2] = (49+4)/(-2)=-53/2=-26,5