\(=bc\left(b+c\right)\)\(+ac^2\)\(-a^2\)\(c\)\(-a^2\)\(b\)\(-ab^2\)
\(=bc\left(b+c\right)\)\(-a^2\)\(\left(b+c\right)\)\(-a\left(b+c\right)\)\(\left(b-c\right)\)
\(=\left(b+c\right)\)\(\left(bc-a^2-ab+ac\right)\)
\(=\left(b+c\right)\)\(\orbr{c\left(b+a\right)-a\left(a+b\right)}\)
\(=\left(b+c\right)\)\(\left(b+a\right)\)\(\left(c-a\right)\)
Tỉ lệ sai 1%