Mk sửa đề:x²-4y²+x+2y=(x-2y)(x+2y)+(x+2y)

                                      =(x+2y)(x=2y+1)

                                                          HOK TỐT NHA BN

a,892²+892.2.108+108²=(892+108)²=1000²

b,36²+26²-2.26.36=(36-26)²=10²

a) x² - 5x - y² -5y

= ( x² - y² ) + ( -5x - 5y)

= ( x - y ) ( x + y) - 5( x + y )

= ( x + y ) ( x - y -5)

b) x³ + 2x² - 4x - 8

= x² ( x + 2 ) - 4 ( x + 2 )

= ( x +2 ) ( x² -4 )

= ( x+2)² ( x-2)

Bai 2 : 

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

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

\(=2x^2+2x+13-2x^2-2x+12=25\)

b, \(B=\left(x-2\right)^2-x\left(x-1\right)\left(x-3\right)+3x^2-9x+8\)

\(=x^2-4x+4-x\left(x^2-3x-x+3\right)+3x^2-9x+8\)

\(=4x^2-13x+12-x^3+4x^2-3x=-16x+12-x^3\)

\(M=\left(\frac{1}{a^2-a}+\frac{1}{a-1}\right):\frac{a+1}{a^2-2a+1}\)

\(M=\left(\frac{1}{a\left(a-1\right)}+\frac{1}{a-1}\right):\frac{a+1}{\left(a-1\right)^2}\)ĐKXĐ : a khác 0, a khác 1

\(M=\frac{1+a}{a\left(a-1\right)}.\frac{\left(a-1\right)^2}{a+1}\)

\(M=\frac{a-1}{a}\)

\(M=\left(\frac{1}{a^2-a}+\frac{1}{a-1}\right):\frac{a+1}{a^2-2a+1}\)DK : \(x\ne0;\pm1\)

\(=\left(\frac{1}{a\left(a-1\right)}+\frac{1}{a-1}\right):\frac{a+1}{\left(a-1\right)^2}=\left(\frac{1}{a\left(a-1\right)}+\frac{a}{a\left(a-1\right)}\right):\frac{a+1}{\left(a-1\right)^2}\)

\(=\frac{a+1}{a\left(a-1\right)}.\frac{\left(a-1\right)^2}{a+1}=\frac{a-1}{a}\)

x² + 5y² - 4xy + 6x - 14y + 10 = 0

=> (x² - 4xy + 4y²) + (6x - 12y) + 9 + (y² - 2y + 1) = 0

=> (x - 2y)² + 6(x - 2y) + 9 + (y - 1)² = 0

=> (x - 2y + 3)² + (y - 1)² = 0

=> \(\hept{\begin{cases}x-2y+3=0\\y-1=0\end{cases}}\Rightarrow\hept{\begin{cases}x=-1\\y=1\end{cases}}\)

Vậy x = 1 ; y = - 1 là giá trị cần tìm

làm nhanh giùm mình nha ! đang cần gấp <:)