Question

Rút gọn biểu thức sau :

a) (a² +a- 1) ( a² - a+1)    

b) ( a+2) (a -2) ( a²+ 2a +4) ( a²- 2a +4)

c) (x-2)² -(x - 3) (x-1)

d) (x-1)³ - (x+1)³ + 6(x+1) (x -1)

e) (2 +3y)²- ( 2x- 3y)² - 12xy

g) (x+ 1)³ - (x-1 )³- (x³ -1 )- (x- 1)(x² +x +1)

h) (x+1) (x² -x+ 1)-( x-1) (x² + x +1 )

 

Answer 1

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

b)\(=\left(a+2\right)\left(a^2-2a+4\right)\left(a-2\right)\left(a^2+2a+4\right)=\left(a^3+8\right)\left(a^3-8\right)=a^6-64\)

c)\(=x^2-4x+4-x^2+x+3x-3=1\)

d)\(=x^3-3x^2+3x-1-x^3-3x^2-3x-1+6x^2-6=-8\)

e) \(=4+12y+9y^2-4x^2+12xy-9y^2-12xy=-4x^2+12y+4\)

g)\(=x^3+3x^2+3x+1-x^3+3x^2-3x+1-x^3+1-x^3+1=-2x^3+6x^2+3\)

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

Answer 2

cảm ơn nhé

Answer 3

Rút gọn biểu thức sau : a) (a2 +a- 1) ( a2 - a+1)

b) ( a+2) (a -2) ( a2+ 2a +4) ( a2- 2a +4)

c) (x-2)2 -(x - 3) (x-1)

d) (x-1)3 - (x+1)3 + 6(x+1) (x -1)

e) (2 +3y)2- ( 2x- 3y)2 - 12xy

g) (x+ 1)3 - (x-1 )3- (x3 -1 )- (x- 1)(x2 +x +1)

h) (x+1) (x2 -x+ 1)-( x-1) (x2 + x +1 )

Giúp mình nhé ><