Решите уравнение: (t²+8t)²+19(t²+8t)+84=0

T²+8t=a
a²+19a+84=0
a1+a2=-19 U a1*a2=84
a1=-12⇒t²+8t=-12
t²+8t+12=0
t1+t2=-8 U t1*t2=12⇒t1=-6 U t2=-2
a2=-7⇒t²+8t=-7
t²+8t+7=0
t3+t4=-8 U t3*t4=7⇒t3=-7 U t4=-1