Bài 1 :

A = x² + 2x + 2

A = 2 + ( x² + 2^x )

A = 2 + X² + 2

A = 2 + 2x²

A = 2¹ + 2x²

A = 2¹ + 2² x x

A = 2² - 2¹

A = 2¹ x

A = 2^X2

A = x = - \(\frac{1}{2}\)

A = x : 1¹ = - \(\frac{1}{2}\)

A = x² : - \(\frac{1}{2}\)

A = - \(\frac{1Z}{2}\)

\(A=x^3-y^3-9xy=\left(x-y\right)\left(x^2+xy+y^2\right)-9xy=3\left(x^2+xy+y^2\right)-9xy\) (vì x - y = 3)

\(=3x^2+3xy+3y^2-9xy=3x^2-6xy+3y^2=3\left(x^2-2xy+y^2\right)=3\left(x-y\right)^2=27\)(vì x - y = 3)

M = ab - (ab + bc + ca) + (a + b + c) - 1

= -(bc + ca) + (a + b) + (c - 1) 

= -c(b + a) + (a + b) + (c - 1) 

= (a + b)(-c + 1) + (c - 1)

Thay c = 1 vào M

=> M = (a + b)(-1 + 1) + (1 - 1) = 0

Vậy M = 0 

Kết quả = 0 nha. Bn thay c =1 r phá ngoặc là tính ra

\(2x^3y-2xy^3-4xy^2-2xy\)

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

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

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

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

Vậy chọn đáp án A

chọn A

\(x^3-x=6\)

\(\Rightarrow x.\left(x^2-1\right)=6\)

\(\Rightarrow x.\left(x-1\right).\left(x+1\right)=6\)

\(x^6-2x^4+x^3+x^2-x\)

\(=x^6-x^5+x^5-x^4-x^4+x^3+x^2-x\)

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

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

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

\(=\left(x-1\right).\left(x+1\right).[x^4-x.\left(x-1\right)]\)

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

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

\(=6.\left(6+1\right)\)

\(=42\)

Vậy giá trị của biểu thức \(B=42\)khi \(x^3-x=6\)

1)2xy−2y²+3x−3y1)2xy−2y²+3x−3y

=2y(x−y)+3(x−y)=2y(x−y)+3(x−y)
=(2y+3)(x−y)=(2y+3)(x−y)

2)x²−9y²+x+3y2)x²−9y²+x+3y

=x²−(3y)²+(x+3y)=x²−(3y)²+(x+3y)

=(x−3y)(x+3y)+(x+3y)=(x−3y)(x+3y)+(x+3y)

=(x−3y+1)(x+3y)=(x−3y+1)(x+3y)
3)3x(2x−3)−6x+93)3x(2x−3)−6x+9
=3x(2x−3)−3(2x−3)=3x(2x−3)−3(2x−3)
=(3x−3)(2x−3)=(3x−3)(2x−3)
=3(x−1)(2x−3)=3(x−1)(2x−3)

4)y²−25−x²−10x4)y²−25−x²−10x
=−(x²+10x+25)+y²=−(x²+10x+25)+y²
=−(x+5)²+y²=−(x+5)²+y²

=y²−(x+5)²=y²−(x+5)²
=(y−x−5)(y+x+5)=(y−x−5)(y+x+5)
5)x²−10x+245)x²−10x+24

=x²−4x−6x+24=x²−4x−6x+24
=x(x−4)−6(x−4)=x(x−4)−6(x−4)
=(x−6)(x−4)