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21 tháng 8 2015

Bài này sử dụng \(a^2-b^2=\left(a-b\right)\left(a+b\right).\)

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

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

b) \(\left(4x^2-3x-18\right)^2-\left(4x^2+3x\right)^2=\left(4x^2-3x-18-4x^2-3x\right)\left(4x^2-3x-18+4x^2+3x\right)\)

\(=\left(-6x-18\right)\left(8x^2-18\right)=-12\left(x+3\right)\left(4x^2-9\right)=-12\left(x+3\right)\left(2x-3\right)\left(2x+3\right).\)

c)  \(\left(4abcd+\left(a^2+b^2\right)\left(c^2+d^2\right)\right)^2-4\left(cd\left(a^2+b^2\right)+ab\left(c^2+d^2\right)\right)^2\)

\(=\left(4abcd+\left(a^2+b^2\right)\left(c^2+d^2\right)-2cd\left(a^2+b^2\right)-2ab\left(c^2+d^2\right)\right)\times\)

\(\times\left(4abcd+\left(a^2+b^2\right)\left(c^2+d^2\right)+2cd\left(a^2+b^2\right)+2ab\left(c^2+d^2\right)\right)\)

\(=\left(\left(a^2+b^2\right)\left(c-d\right)^2-2ab\left(c-d\right)^2\right)\times\left(\left(a^2+b^2\right)\left(c+d\right)^2+2ab\left(c+d\right)^2\right)\)

\(=\left(c-d\right)^2\cdot\left(a-b\right)^2\cdot\left(a+b\right)^2\cdot\left(c+d\right)^2.\)

 

20 tháng 8 2016

2/ (b- 4b+ 4) - 9a= (b- 2) - 9a= (b- 2 + 3a)(b- 2 - 3a)

20 tháng 8 2016

3/ (x+1)(x+ x + 1)[x + (√13 - 7)/6][3x - (√13 + 7)/2]

23 tháng 8 2016

a/ (x - 1)(x - √3 + 2)(x + √3 + 2)

23 tháng 8 2016

a ) \(x^3+3x^2-3x+1\)

    \(=x^3-3x+3x^2-1\)

     \(=\left(x-1\right)^3\)

   

a) Ta có: \(\left(4x^2-3x-18\right)^2-\left(4x^2+3x\right)^2\)

\(=\left(4x^2-3x-18-4x^2-3x\right)\left(4x^2-3x-18+4x^2+3x\right)\)

\(=\left(-6x-18\right)\left(8x^2-18\right)\)

\(=-6\left(x+3\right)\cdot2\left(4x^2-9\right)\)

\(=-12\left(x+3\right)\left(2x-3\right)\left(2x+3\right)\)

b) Ta có: \(9\left(x+y-1\right)^2-4\left(2x+3y+1\right)^2\)

\(=\left(3x+3y-3\right)^2-\left(4x+6y+2\right)^2\)

\(=\left(3x+3y-3-4x-6y-2\right)\left(3x+3y-3+4x+6y+2\right)\)

\(=-\left(x+3y+5\right)\left(7x+9y-1\right)\)

c) Ta có: \(-4x^2+12xy-9y^2+25\)

\(=-\left(4x^2-12xy+9y^2-25\right)\)

\(=-\left[\left(2x-3y\right)^2-25\right]\)

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

d) Ta có: \(x^2-2xy+y^2-4m^2+4mn-n^2\)

\(=\left(x^2-2xy+y^2\right)-\left(4m^2-4mn+n^2\right)\)

\(=\left(x-y\right)^2-\left(2m-n\right)^2\)

\(=\left(x-y-2m+n\right)\left(x-y+2m-n\right)\)

a: \(ab+a+b+1\)

\(=a\left(b+1\right)+\left(b+1\right)\)

\(=\left(b+1\right)\left(a+1\right)\)

c: \(4x^2-12xy+3x-9y\)

\(=4x\left(x-3y\right)+3\left(x-3y\right)\)

\(=\left(x-3y\right)\left(4x+3\right)\)

1 tháng 11 2021

1D  2C

Câu 1: D

Câu 2: C

5 tháng 9 2017

a) 4x2 + 4x - 3x = 4x2 +x = x( 4x+1)

b) x2+7x+10= x2+2x+5x+10= x(x+2)+5(x+2)= (x+5)(x+2)

c) x2-x-12= x- 4x+3x-12= x(x-4)+3(x-4)=(x+3)(x-4)

d) x2+3x-18=x2+6x-3x-18= x(x+6)-3(x+6)=(x-3)(x+6)

23 tháng 9 2018

\(x^2+7x+10\)

\(=x^2+2x+5x+10\)

\(=x\left(x+2\right)+5\left(x+2\right)\)

\(=\left(x+2\right)\left(x+5\right)\)

15 tháng 7 2018

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

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

\(=\left[\left(b+c\right)^2-a^2\right]\left[a^2-\left(b-c\right)^2\right]\)

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

b) \(\left(ax+by\right)^2-\left(ay+bx\right)^2\)

\(=\left(ax+by+ay+bx\right)\left(ax+by-ay-bx\right)\)

\(=\left(a+b\right)\left(x+y\right)\left(a-b\right)\left(x-y\right)\)

c) \(\left(a^2+b^2-5\right)^2-4\left(ab+2\right)^2\)

\(=\left(a^2+b^2-5+2ab+4\right)\left(a^2+b^2-5-2ab-4\right)\)

\(=\left[\left(a+b\right)^2-1\right]\left[\left(a-b\right)^2-9\right]\)

\(=\left(a+b+1\right)\left(a+b-1\right)\left(a-b+3\right)\left(a-b-3\right)\)

d) \(\left(4x^2-3x-18\right)^2-\left(4x^2+3x\right)^2\)

\(=\left(4x^2-3x-18+4x^2+3x\right)\left(4x^2-3x-18-4x^2-3x\right)\)

\(=\left(8x^2-18\right)\left(-6x-18\right)\)

\(=\left[2\left(4x^2-9\right)\right]\left[-6\left(x+3\right)\right]\)

\(=12\left(2x+3\right)\left(2x-3\right)\left(x+3\right)\)

3 tháng 10 2021

a) \(4x\left(a-b\right)+6xy\left(b-a\right)\)

\(=4x\left(a-b\right)-6xy\left(a-b\right)\)

\(=\left(4x-6xy\right)\left(a-b\right)\)

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

3 tháng 10 2021

b) \(\left(6x+3\right)-\left(2x-5\right)\left(2x+1\right)\)

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

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

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

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