\(B=\left(y-3\right)\left(y+3\right)\left(y^2+9\right)-\left(y^2+2\right)\left(y^2-2\right)\)\(=\left(y^2-9\right)\left(y^2+9\right)-\left(y^4-4\right)\)\(=y^4-81-y^4+4=-77\)Câu trả lời: \(B=\left(y-3\right)\left(y+3\right)\left(y^2+9\right)-\left(y^2+2\right)\left(y^2-2\right)\)\(=\left(y^2-9\right)\left(y^2+9\right)-\left(y^4-4\right)\)\(=y^4-81-y^4+4=-77\)