a) 3(x-1)-2|x+3| = 3x-3-2(x+3) = 3x-3-2x+6 = (3x-2x)+(6-3)=x+3

b) 2|x-3|-|4x-1| = 2(x-3)-(4x-1) = 2x-6-4x+1 = (2x-4x)-(6-1) = -2x-5

A= -x-y+z+x+y+z=2z

A=2*(-501)=-1002

cách 2 A= (-x-y)+z-(-x-y)+z= 2z

Bạn Võ Ngọc Trường An ơi bạn có thể giải chi tiết hơn cho mk được ko

Mk ko biết  kb nha 

a) (x-y)²-(x²-2xy)

=y²-2xy+x²-x²+2xy

=y²-(-2xy+2xy)+(x²-x²)

=y²

b)(x-y)²+x²+2xy-(x+y)²

=y²-2xy+x²+x²+2xy-y²-2xy-x²

=(y²-y²)-(2xy+2xy-2xy)+(x²+x²-x²)

=x²-2xy

1. -4x( x + 3 )( x - 4 ) - 3x( x² - x + 1 )

= -4x( x² - x - 12 ) - 3x( x² - x + 1 )

= -4x³ + 4x² + 48x - 3x³ + 3x² - 3x

= -7x³ + 7x² + 45x

2. a) 4x( x - 5 ) - ( x - 1 )( 4x - 3 ) = 5

<=> 4x² - 20x - ( 4x² - 7x + 3 ) = 5

<=> 4x² - 20x - 4x² + 7x - 3 = 5

<=> -13x - 3 = 5

<=> -13x = 8

<=> x = -8/13

b) 6( x - 3 )( x - 4 ) - 6x( x - 2 ) = 4

<=> 6( x² - 7x + 12 ) - 6x² + 12x = 4

<=> 6x² - 42x + 72 - 6x² + 12x = 4

<=> -30x + 72 = 4

<=> -30x = -68

<=> x = 34/15

Bài 1 : 

\(-4x\left(x+3\right)\left(x-4\right)-3x\left(x^2-x+1\right)\)

\(=-7x^3+7x^2+45x\)

Bài 2 : 

a, \(4x\left(x-5\right)-\left(x-1\right)\left(4x-3\right)=5\)

\(\Leftrightarrow4x^2-20x-\left[4x^2-7x+3\right]=5\)

\(\Leftrightarrow4x^2-20x-4x^2+7x-3=5\)

\(\Leftrightarrow-13x-8=0\Leftrightarrow x=-\frac{8}{13}\)

b, \(6\left(x-3\right)\left(x-4\right)-6x\left(x-2\right)=4\)

\(\Leftrightarrow6x^2-42x+72-6x^2+12x=4\)

\(\Leftrightarrow-30x+68=0\Leftrightarrow x=\frac{34}{15}\)

\(\left|2x-\frac{1}{2}\right|+1=3x\)

\(\Leftrightarrow\left|2x-\frac{1}{2}\right|=3x-1\)

\(\Leftrightarrow\orbr{\begin{cases}2x-\frac{1}{2}=3x-1\\2x-\frac{1}{2}=1-3x\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}2x-3x=-1+\frac{1}{2}\\2x+3x=1+\frac{1}{2}\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}-x=-\frac{1}{2}\\5x=\frac{3}{2}\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{2}\\x=\frac{3}{10}\end{cases}}\)