ai dám trả lời câu hỏi của tôi thì tôi thưởng 6 cho 3 người nhanh nhất

a          A=a+b-4a+b-a-c

               =4-a-c

tích cho mình nhé

a           A=a+b-4a+b-a-b

               =4-a-b

A = a + b + 4a + b - a - c

= (a + 4a - a) + (b + b) - c

= 4a + 2b - c

B = a + b - c + a - b + c + b - c + a + 2a + b + c

= (a + a + a + 2a) + (b - b + b + b) + (-c + c - c + c)

= 5a + 2b + 0

= 5a + 2b.

A =  ( a + b ) - ( - 4a - b ) - ( a + c )

A = a + b - (-4a) + b - a - c

A = a + b + 4a + b - a - c

A = ( a + 4a - a ) + ( b + b ) - c

A = 4a + 2b - c

Câu B tương tự nha bạn!

(a+b)-(a-b)+(a-c)-(a+c)=a+b-a+b+a-c-a-c=a-a+b+b+a-a-c-c=2b-2c=2(b-c)

nhớ k cho mink nhé

Giải:

\(A=\left(a+b\right)-\left(a-b\right)+\left(a-c\right)-\left(a+c\right)\)

\(\Leftrightarrow A=a+b-a+b+a-c-a-c\)

\(\Leftrightarrow A=\left(a-a+a-a\right)+\left(b+b\right)+\left(-c-c\right)\)

\(\Leftrightarrow A=2b-2c\)

\(\Leftrightarrow A=2\left(b-c\right)\)

Vậy ...

a)

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

A = a + b - a + b + a- c - a - c

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

= 2b -2c

a) `A=(a+b)-(a-b)+(a-c)-(a+c)`

`=a+b-a+b+a-c-a-c`

`=2b-2c`

b) `B=(a+b-c)+(a-b+c)-(b+c-a)-(a-b-c)`

`=a+b-c+a-b+c-b-c+a-a+b+c`

`=2a`

\(A=\left(a+b\right)-\left(a-b\right)+\left(a-c\right)-\left(a+c\right)\)

\(A=a+b-a+b+a-c-a-c\)

\(A=2b-2c\)

\(B=\left(a+b-c\right)+\left(a-b+c\right)-\left(b+c-a\right)-\left(a-b-c\right)\)

\(B=a+b-c+a-b+c-b-c+a-a+b+c\)

\(B=2a\)

a) \(A=\left(a+b\right)-\left(a-b\right)+\left(a-c\right)-\left(a+c\right)\) 

\(A=a+b-a+b+a-c-a-c\) 

\(A=\left(a-a+a-a\right)+\left(b+b\right)+\left(-c-c\right)\) 

\(A=0+2b+-2c\) 

\(A=2b-2c\) 

b) \(B=\left(a+b-c\right)+\left(a-b+c\right)-\left(b+c-a\right)-\left(a-b-c\right)\) 

\(B=a+b-c+a-b+c-b-c+a-a+b+c\) 

\(B=\left(a+a+a-a\right)+\left(b-b-b+b\right)+\left(-c+c-c+c\right)\) 

\(B=2a+0+0\) 

\(B=2a\)

a)(a+b)-(a-b)+(a-c)-(a+c) 

=a+b-a+b+a-c-a-c

=2b-2c

b)(a+b-c)+(a-b+c)-(b+c-a)-(a-b-c)

=a+b-c+a-b+c-b-c+a-a+b+c

=2a

Giải:

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

    A=a+b-a+b+a-c-a-c

    A=0+(a-a)-c-c

    A=0+0-c-c

    A=-c-c

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

    B=a+b-c+a-b+c-b-c+a-a+b+c

    B=(a+a+a-a)+(b-b-b+b)+(-c+c-c+c)

    B=(a+a)+0+0

    B=a+a

Chúc bạn học tốt!

Làm lại:

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

    A=a+b-a+b+a-c-a-c

    A=(a-a+a-a)+(b+b)+(-c-c)

    A=(b+b)+(-c-c)

    A=2b-2c

Chúc bạn học tốt!

$A = (a + b) - (a + b) + (a - c) - (a + c)$

$A=a+b-a-b+a-c-a-c$

$A=-2c$

A = (a + b) - (a - b) + (a - c) - (a + c)
A = a + b - a + b + a - c - a - c
A = 2b