câu này gửi rồi mà tôi lm rồi đó Câu hỏi của nguyen thi diem quynh - Toán lớp 8 - Học toán với OnlineMath

a. 1+6x-6x²-x³
=(1-x³)+(6x-6x²) 
=(1-x)(1+x+x²)+6x(1-x) 
=(1-x)(1+x+x²+6x) 
=(1-x)(1+7x+x²) 

b. x³-2x-4 
=x³-4x+2x-4 
=x(x²-4)+2(x-2) 
=x(x-2)(x+2)+2(x-2) 
=(x²+2x+2)(x-2) 
 Ủng hộ mk nhak ^_-

−5𝑥^2−8𝑥+4

\(=\left[2\left(x-1\right)-3x\right]\left[2\left(x-1\right)+3x\right]\\ =\left(2x-2-3x\right)\left(2x-2+3x\right)\\ =\left(-2-x\right)\left(5x-2\right)\\ =\left(x+2\right)\left(2-5x\right)\)

\(4\left(x-1\right)^2-9x^2=\left(2x-2\right)^2-\left(3x\right)^2=\left(2x-2-3x\right)\left(2x-2+3x\right)=\left(-x-2\right)\left(5x-2\right)=-\left(x+2\right)\left(5x-2\right)=\left(x+2\right)\left(2-5x\right)\)

         \(x^4+6x^3+11x^2+6x+1\)

\(=\left(x^4+6x^3+9x^2\right)+2\left(x^2+3x\right)+1\)

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

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

Chúc bạn học tốt.

a, \(x^3-6x^2+9x\)

\(=x\left(x^2-6x+9\right)\)

\(=x \left(x-3\right)\)

Câu b, c cũng tượng tự nha bn , dễ mà 

#hoc_tot#

b) \(x^2-2xy+3x-6y=x\left(x-2y\right)+3\left(x-2y\right)=\left(x-2y\right)\left(x+3\right)\)

c)\(x^2-8x+7=x^2-x-7x+7=x\left(x-1\right)-7\left(x-1\right)=\left(x-1\right)\left(x-7\right)\)

a)\(x^3-6x^2+9x=x\left(x^2-2\cdot x\cdot3+3^2\right)=x\left(x-3\right)^2\)

                                                                              ~ Chúc bạn học tốt ~

a,= \(x\left(x-3\right)^2\)

b, = \(x\left(x-2y\right)+3\left(x-2y\right)\)

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

c, = \(x^2-7x-x+7\)

= \(x\left(x-7\right)-\left(x-7\right)\)

= \(\left(x-1\right)\left(x-7\right)\)

hok tốt

............

\(2x\left(2x-5\right)-6x+15=2x\left(2x-5\right)-3\left(2x-5\right)=\left(2x-5\right)\left(2x-3\right)\)

a) \(x^3+x^2y-x^2z-xyz\)

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

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

\(=x\left(x+y\right)\left(x-z\right)\)

b) \(x^2-6x+9-9y^2\)

\(=\left(x^2-2\cdot x\cdot3+3^2\right)-\left(3y\right)^2\)

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

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

c) \(x^2+9x+20\)

\(=x^2+5x+4x+20\)

\(=x\left(x+5\right)+4\left(x+5\right)\)

\(=\left(x+5\right)\left(x+4\right)\)

d) \(x^4+4\)

\(=\left(x^2\right)^2+2\cdot x^2\cdot2+4-2\cdot x^2\cdot2\)

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

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

a/\(x^3+x^2y-x^2z-xyz\)

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

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

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

b/\(x^2-6x+9-9y^2\)

\(=\left(x^2-6x+9\right)-9y^2\)

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

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

c/\(x^2+9x+20\)

\(=x^2+4x+5x+20\)

\(=\left(x^2+4x\right)+\left(5x+20\right)\)

\(=x\left(x+4\right)+5\left(x+4\right)\)

\(=\left(x+5\right)\left(x+4\right)\)

d/\(x^4+4\)

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

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

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

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

\(a,x^3+x^2y-x^2z-xyz=x^2\left(x+y\right)-xz\left(x+y\right).\)

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

\(=x\left(x+y\right)\left(x-z\right)\)

\(b,x^2-6x+9-9y^2=\left(x-3\right)^2-9y^2\)

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

\(c,x^2+9x+20=\left(x^2+8x+16\right)+\left(x+4\right)\)

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

\(=\left(x+4\right)\left(x+4+1\right)=\left(x+4\right)\left(x+5\right)\)

\(d,x^4+4=\left(x^2\right)^2+2^2\)

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

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