−12,4(x−12)(x+34)=0 . Найдите корни уравнения Пожалуйста

−12.4(x2+34x−12x−408)−12.4(x2+22x−408)=0−12.4x2−272.8x+5059.2=0​ 
begin{lgathered}12.4 {x}^{2} + 272.8x \ - 5059.2 = 0 div 12.4 \ {x}^{2} + 22x - 408 = 0end{lgathered}12.4x2+272.8x−5059.2=0÷12.4x2+22x−408=0​ 
begin{lgathered}d = 484 + 1632 = 2116 = {46}^{2} \ x1 = frac{ - 22 + 46}{2} = frac{24}{2} = 12end{lgathered}d=484+1632=2116=462x1=2−22+46​=224​=12​ 
x2 = frac{ - 22 - 46}{2} = - frac{68}{2} = - 36x2=2−22−46​=−268​=−36