Question

Решите уравнение
3(5x+2)^2 + 10(5x+2) + 3 = 0

Answer 1

$\displaystyle 3(5x+2)^2+10(5x+2)+3=0\\3(25x^2+20x+4)+50x+20+3=0\\75x^2+60x+12+50x+20+3=0\\75x^2+110x+35=0\\15x^2+22x+7=0\\\\x=\frac{-22б\sqrt{22^2-4*15*7} }{2*15}=\frac{-22б\sqrt{484-420} }{30}=\frac{-22б\sqrt{64} }{30}=\frac{-22б8}{30}\\\\x_1=-1,x_2=-\frac{7}{15}$