a, Ta có: \(=4a^2b^2-\left(2a^2b^2-2b^2c^2-2c^2a^2+a^4+b^4+c^4\right)\)
\(=\left(2ab\right)^2-\left(a^2+b^2-c^2\right)^2\)
\(=\left(2ab-a^2-b^2+c^2\right)\left(2ab+a^2+b^2-c^2\right)\)
b, ta có: \(=\left(x^8+2x^4+1\right)-x^4\)
\(=\left(x^4+1\right)^2-\left(x^2\right)^2\)
\(=\left(x^4+1-x^2\right)\left(x^4+1+x^2\right)\)
CHÚC BẠN HỌC TỐT....