ko pt đc nha bạn

thanks

\(=16-\left(x^2-2xy+y^2\right)\)

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

25n(n-1)-50(n-1) luôn chia hết cho 150 với mọi n là số nguyên

giúp mình chứng minh nha . Cám ơn mấy bạn

= x³+x²-x²-x+2x+2

=x²(x+1)-x(x+1)+2(x+1)

=(x+1)(x²-x+2)

Cám ơn nhaa

\(=\left(x-y+5-1\right)^2=\left(x-y+4\right)^2\)

(x-y+5)^2-2.1,(x-y+5)+1

(x-y+5-1)^2

(x-y+4)^2

(x-y+5)^2-2(x-y+5)+1

=(x−y+5−1)2

=(x−y+4)2

x²  - (y² -6y +9)

x² - (y - 3)²

(x+y-3)(x-y+3)

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

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

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

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

a) ( x-2 )( x - 4 )(  x - 6 )( x  -8  ) + 15 

= ( x-  2 )( x - 8 )( x -  4)( x- 6  ) + 15

= ( x^2 - 10x + 16 )( x^2 - 10x + 24 ) + 15 

Đắt x^2 + x + 16 = y 

= y ( y + 8 ) + 15

= y^2 + 8y + 15

=  y^2 + 3y + 5y  + 15

=y ( y + 3 ) + 5 ( y + 3 )

= ( y+  5)( y + 3)

Thay vào