\(a,a^2-2a-4b^2-4b\)

\(=\left(a^2-4b^2\right)-\left(2a+4b\right)\)

\(=\left(a-2b\right)\left(a+2b\right)-2\left(a+2b\right)\)

\(=\left(a+2b\right)\left(a-2b-2\right)\)

\(b,x^3-2x^2+4x-8\)

\(=x^2\left(x-2\right)+4\left(x-2\right)\)

\(=\left(x-2\right)\left(x^2+4\right)\)

\(c,x^3+36x-12x^2\)

\(=x^3-6x^2-6x^2+36x\)

\(=x^2\left(x-6\right)-6x\left(x-6\right)\)

\(=\left(x-6\right)\left(x^2-6x\right)\)

\(=x\left(x-6\right)^2\)

\(d,5a^2+3\left(a+b\right)^2-5b^2\)

\(=\left(5a^2-5b^2\right)+3\left(a+b\right)^2\)

\(=5\left(a^2-b^2\right)+3\left(a+b\right)^2\)

\(=5\left(a-b\right)\left(a+b\right)+3\left(a+b\right)^2\)

\(=\left(a+b\right)\left[5\left(a-b\right)+3\left(a+b\right)\right]\)

\(=\left(a+b\right)\left(5a-5b+3a+3b\right)\)

\(=\left(a+b\right)\left(8a-2b\right)\)

\(=2\left(a+b\right)\left(4a-b\right)\)

\(e,x^3-3x^2+3x-1-y^3\)

\(=\left(x^3-3x^2+3x-1\right)-y^3\)

\(=\left(x-1\right)^3-y^3\)

\(=\left(x-1-y\right)\left[\left(x-1\right)^2+\left(x-1\right)y+y^2\right]\)

\(=\left(x-y-1\right)\left(x^2-2x+1+xy-y+y^2\right)\)

\(=\left(x-y-1\right)\left(x^2+y^2-xy-y+1\right)\)

#Urushi☕

\(c.\\ x^3+36x-12x^2\\ =x\left(x^2-12x+36\right)\\ =x.\left(x^2-2.x.6+6^2\right)\\ =x.\left(x-6\right)^2\\ ---\\ d.\\ 5a^2+3\left(a+b\right)^2-5b^2\\ =\left(5a^2-5b^2\right)+3\left(a+b\right)^2\\ =5.\left(a^2-b^2\right)+3.\left(a+b\right)\left(a+b\right)\\ =5\left(a+b\right)\left(a-b\right)+3\left(a+b\right)\left(a+b\right)\\ =\left(a+b\right)\left(5a-5b+3a+3b\right)\\ =\left(a+b\right)\left(8a-2b\right)\\ =2\left(a+b\right)\left(4a-b\right)\)

\(e.\\ x^3-3x^2+3x-1-y^3\\ =\left(x-1\right)^3-y^3\\ =\left(x-1-y\right)\left[\left(x-1\right)^2+\left(x-1\right).y+y^2\right]\\ =\left(x-y-1\right).\left[\left(x^2-2x+1\right)+y\left(x+y-1\right)\right]\)

\(a.\\ a^2-2a-4b^2-4b\\ =\left(a^2-2a+1\right)-\left(4b^2-4b+1\right)\\ =\left(a-1\right)^2-\left(2b-1\right)^2\\ =\left[\left(a-1\right)+\left(2b-1\right)\right].\left[\left(a-1\right)-\left(2b-1\right)\right]\\ =\left(a+2b-2\right)\left(a-2b\right)\)

\(b.\\ x^3-2x^2+4x-8=x^2\left(x-2\right)+4\left(x-2\right)\\ =\left(x^2+4\right)\left(x-2\right)\)

\(5a^2-14ab-3b^2\\ =5a^2-15ab-ab-3b^2\\ =5a\left(a-3b\right)-b\left(a-3b\right)\\ =\left(5a-b\right)\left(a-3b\right)\)

\(5a^2-14ab-3b^2\)

\(=5a^2-15ab+ab-3b^2\)

\(=5a\left(a-3b\right)+b\left(a-3b\right)\)

\(=\left(a-3b\right)\left(5a+b\right)\)

=(5a²+5b²+10ab)-5c²=5.(a²+2ab+b²)-5c²=5.(a+b)²-5c²=5.[(a+b)²-c²]=5.(a+b+c).(a+b-c)

=(5a²+5b²+10ab)-5c²=5.(a²+2ab+b²)-5c²=5.(a+b)²-5c²=5.[(a+b)²-c²]=5.(a+b+c).(a+b-c)

Đa thức không phân tích được bạn ơi

3a²- 10ab +3b² =(3a² -9ab) -( ab-3b²) = 3a(a-3b) - b(a-3b) =(a-3b)(3a-b)

a) \(x^6-y^6\)

\(=\left(x^3\right)^2-\left(y^3\right)^2\)

\(=\left(x^3-y^3\right)\left(x^3+y^3\right)\)

\(=\left(x-y\right)\left(x^2+xy+y^2\right)\left(x+y\right)\left(x^2-xy+y^2\right)\)

b) \(10ab+0,25a^2+100b^2\)

\(=\left(0,5a\right)^2+2\cdot0,5a\cdot10b+\left(10b\right)^2\)

\(=\left(0,5a+10b\right)^2\)

c) \(9x^2-xy+\frac{1}{36}y^2\)

\(=\left(3x\right)^2-2\cdot3x\cdot\frac{1}{6}y+\left(\frac{1}{6}y\right)^2\)

\(=\left(3x-\frac{1}{6}y\right)^2\)

\(-8x^3+1=1^3-\left(2x\right)^3=\left(1-2x\right)\left(1+2x+4x^2\right)\)

Ta có

12 x 3 y   –   6 x y   +   3 x y 2     =   3 x y . 4 x 2   –   3 x y . 2   +   3 x y . y   =   3 x y ( 4 x 2   –   2   +   y )

Đáp án cần chọn là: A

Ta có 7 x 2 y 2   –   21 x y 2 z   +   7 x y z   +   14 x y

= 7xy.xy – 7xy.3yz + 7xy.z + 7xy.2 = 7xy(xy – 3yz + z + 2)

Đáp án cần chọn là: D