1: \(=\left(a^2+b^2-5\right)^2-\left(2ab+4\right)^2\)
\(=\left(a^2+b^2-5+2ab+4\right)\left(a^2+b^2-5-2ab-4\right)\)
\(=\left[\left(a+b\right)^2-1\right]\left[\left(a-b\right)^2-9\right]\)
\(=\left(a+b+1\right)\left(a+b-1\right)\left(a-b-3\right)\left(a-b+3\right)\)
2: Đặt x-y=a; y-z=b
Biểu thức sẽ là \(a^3+b^3-\left(a+b\right)^3\)
\(=3ab\left(a+b\right)\)
\(=3\left(x-y\right)\left(y-z\right)\left(x-z\right)\)
1) Đề bài
(a2+2b−5)×2−4(ab+2)×2
2(a2+2b−5)−4(ab+2)×2
2(a2+2b−5)−8(ab+2
2a2+4b−10−8(ab+2)
2a2+4b−10−(8ab+16)
2a2+4b−10−8ab−16
2a2+4b+(−10−16)−8ab
2a2+4b−26−8ab
