Câu 1 : x²-y²+2yz-z²=-(y²-2yz+z²-x²)                    Câu 2: x²-2xy+y²-xz+yz=(x²-2xy+y²)-xz+yz

                                 =-(y-z)² -x²                                                                   =(x-y)²-z(x-y)

                                        =-(y-z-x)(y-z+x)                                                            =(x-y)(x-y-z)

x² - 2xy + tx - 2ty

= x(x+t) - 2y(x+t)

= (x+t)(x-2y) 

`#3107.101107`

`b/(a - b) + a/(b - a)`

`= b/(a - b) - a/(a - b)`

`= (b - a)/(a - b)`

`= -(a - b)/(a - b)`

`= -1`

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

x-y²+x²-y

=(x-y)+(x²-y²)

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

=(x-y)(1+x+y)

x³ - 3x² - 4x + 12

= x²(x-3) - 4(x-3)

= (x-3)(x² -4)

=(x-3)(x-2)(x+2)

\(x^3-3x^2-4x+12\)

\(=\left(x^3-3x^2\right)-\left(4x-12\right)\)

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

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

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

x² - 2xy - 4z² + y²

= (x² - 2xy+y²) - (2z)²

= (x-y)²- (2z)²

= (x-y-2z)(x-y+2z)

x²-2xy-4z²+y²

=(x²-2xy+y²)-(2z)²

=(x-y)²-(2z)²

=(x-y-2z)(x-y+2z)

x^2 - 2xy - (4z)^2 + y^2

=(x-y)^2 - (4z)^2

= (x-y-4z)(x-y+4z)

Câu 1: 3x² - 6xy + 3y² - 12z²

= 3(x² - 2xy + y² - 4z²)

= 3[(x² -2xy+y²)- (2z)²]

= 3[(x-y)² - (2z)²]

=3(x-y-2z)(x-y +2z)

Câu 2: x² - 6xy - 25z²+ 9y²

= x² - 2x.3y + (3y)² - (5z)²

= (x-3y)² - (5z)²

= (x-3y-5z)(x-3y+5z) 

\(5x^3-5x^2y-10x^2+10xy=5x^2\left(x-y\right)-10x\left(x-y\right)=5x\left(x-2\right)\left(x-y\right)\)

5x² - 10xy + 5y² - 20z²

=5(x² - 2xy + y² - 4z²)

= 5[ (x² - 2xy + y²) - (2z)²]

= 5[(x-y)² - (2z)²]

= 5(x-y-2z)(x-y+2z)

5x²-10xy+5y²-20z²

=5(x²-2xy+y²-4z²)

=5[(x-y)²-(2z)²]

=5(x-y-2z)(x-y+2z)

ai nhanh đc k

\(\sqrt{1}=8\)

\(\frac{9}{8}=\sqrt{\hept{\begin{cases}2\\\\\end{cases}}}\)

\(^6\)

Quy đồng p/s

a/b=a.m/b.m

Rút gọn p/s

a/b=a:m/b:m

Cộng trừ p/s

cùng mẫu:

a/b+c/b=a+c/b

a/b-c/b=a-c/b 

khác mẫu: 

quy đồng rồi làm y như cùng mẫu