Question

Решите уравнение 5х(х+5)=-30

Answer 1

$5x(x+5)=-30 \ 5 x^{2} +25x+30=0 \ x^{2} +5x+6=0 \ D = b^{2} -4ac=25-24=1 \ x_{1} = frac{-b+ sqrt{D} }{2a}} = frac{-5+1}{2}=-2 \ x_{2} = = frac{-b- sqrt{D} }{2a}} = frac{-5-1}{2}= -3$

Ответ: x =  -3; x = -2.