Question

Bài 1: Khai triển hằng đẳng thức:
a, ( x - y + 2z )2 
b, ( 2x-3 ). ( 2x+3 ) . ( 4x²+9 )
Bài 2: Rút gọn biểu thức:
a, ( 5x+2 ).( 2-5x ) - ( 3x+2 ).( 2x+5 )²
b, ( -2x-3 )² + 2(2x+1).( 2x+5 ) + ( 2x+5 )²
 

Answer 1

Answer 2

Answer 3

Bài 1:

a, \(\left(x-y+2z\right)^2=x^2+y^2+4z^2-2xy-4yz+4zx\)

b, \(\left(2x-3\right)\left(2x+3\right)\left(4x^2+9\right)=\left(4x^2-9\right)\left(4x^2+9\right)=16x^4-81\)

 

Answer 4

Bài 1: 

a)\(\left(x-y+2z\right)^2=\left(x-y\right)^2+2\left(x-y\right).2z+\left(2z\right)^2=x^2+y^2+4z^2-2xy+4xz-4yz\)b) \(\left(2x-3\right)\left(2x+3\right).\left(4x^2+9\right)=\left(4x^2-9\right)\left(4x^2+9\right)=16x^4-81\)

Bài 2:

a) \(\left(5x+2\right)\left(2-5x\right)-\left(3x+2\right)\left(2x+5\right)^2=4-25x^2-\left(3x+2\right)\left(4x^2+20x+25\right)=4-25x^2-12x^3-60x^2-75x-8x^2-40x-50=-12x^3-93x^2-115x-46\)b) \(\left(-2x-3\right)^2+2\left(2x+1\right)\left(2x+5\right)+\left(2x+5\right)^2=4x^2+12x+9+8x^2+24x+10+4x^2+20x+25=16x^2+56x+44\)

Answer 5

Bài 2:

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

\(=-\left(5x+2\right)\left(5x-2\right)-\left(3x+2\right)\left(4x^2+20x+25\right)\)

\(=-\left(25x^2-4\right)-\left(12x^3+60x^2+75x+8x^2+40x+50\right)\)

\(=-25x^2+4-12x^3-60x^2-75x-8x^2-40x-50\)

\(=-12x^3-93x^2-115x-46\)

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

\(=\left(4x^2+12x+9\right)+2\left(4x^2+2x+2x+5\right)+\left(4x^2+20x+25\right)\)

\(=4x^2+12x+9+8x^2+4x+4x+10+4x^2+20x+25\)

\(=16x^2+40x+44\)

Answer 6

Em ơi lâu đài tình ái đó!!!!