(5x-9)³+(11-5x)³=386
(5x-9+11-5x)[(5x-9)²-(5x-9)(11-5x)+(11-5x)²]=386
2[(5x-9)²-5x(11-5x)-9(11-5x)+(11-5x)²]=386
(5x-9)²-5x(11-5x)-9(11-5x)+(11-5x)²=193
25x²-90x+81-55x+25x²-99+45x+121-110x+25x²=193
(25x²+25x²+25x²)-(90x+55x-45x+110x)+(81-99+121)=193
75x²-210x+103=193
75x²-210x=90
75x.(x-2,8)=90
Mk chỉ làm đc đến đây thôi nha
Cho mk xin hay nhất please
Thank you
#Muoi