Bỏ dấu ngoặc rồi thu gọn biểu thức sau:

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

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

=2b-2c

=2(b-c)

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

=3a+3b-3b

=3(a+b-c)

a)

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

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

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

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

=2a

Bỏ dấu ngoặc của biểu thức :

a) a+(b+c) = a+b+c

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

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

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

kết quả với a=0, b=1, c=-2 thì theo mk nghĩ là bn đã tính đúng rồi nha

a) a+(b+c) = a+b+c

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

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

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

mik la hsg toan dang nay mik hok r

a, a+b+b

b,a-b+c

c, a+b-c

d, a+b+c

ktra kq~

a, 0+1+-2=-1    và  0+(1+-2)=-1

...... Tự làm nhô ( cho tui 1 tym đi muwfkkk)

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

b, \(-\left(a-c\right)-\left(a-b+c\right)=-a+c-a+b-c=-2a+b\)

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

d, \(-\left(a-b+c\right)-\left(a+b+c\right)=-a+b-c-a-b-c=-2a-2c\)

Cảm ơn bạn んuﾘ ｲ nhiều lắm!

mik chỉ nhận câu TL sớm nhất thui 

ai Tl nhanh mik tick cho

a) 45-175- - 130= - 260 

Ta có :

\(\left(a+b+c\right)\left(a+b+c\right)-2\left(ab+bc+ca\right)\)

\(=a^2+ab+ac+ba+b^2+bc+ca+cb+c^2-2ab-2bc-2ca\)

\(=\left(a^2+b^2+c^2\right)+\left(ab+ac+ba+bc+ca+cb-2ab-2bc-2ca\right)\)

\(=a^2+b^2+c^2\)

\(\left(a+b+c\right).\left(a+b+c\right)-2.\left(a.b+b.c+c.a\right)\)

\(=a^2+b^2+c^2-\left(2ab+2bc+2ca\right)\)

\(=a^2+b^2+c^2-2ab-2bc-2ca\)

\(=a^2-2ab+b^2-2bc+c^2-2ca\)

\(=\left(a-2b\right)a+\left(b-2c\right)b+\left(c-2a\right)c\)

Chúc bn học tốt

\(\text{(a+b+c).(a+b+c)-2(a.b+b.c+c.a}\)

\(=a.a+a.b+a.c+b.a+b.b+b.c+c.a+c.b+c.c-2.\left(a.b+b.c+c.a\right)\)

\(=\left(a^2+b^2+c^2\right)+a.b+a.c+b.a++b.c+c.a+c.b-2.a.b-2.b.c-c.a.2\)

\(=a^2+b^2+c^2\)

Vậy.......

Học tốt!

MTC: \(abc\left(a-b\right)\left(b-c\right)\left(a-c\right)\)nên

\(A=\frac{bc\left(b-c\right)\left(a-2\right)\left(a-1014\right)}{abc\left(a-b\right)\left(a-c\right)\left(b-c\right)}+\frac{ac\left(a-c\right)\left(b-2\right)\left(b-1004\right)}{abc\left(a-b\right)\left(b-c\right)\left(a-c\right)}+\frac{ab\left(a-b\right)\left(c-2\right)\left(c-1004\right)}{abc\left(a-c\right)\left(a-b\right)\left(b-c\right)}\)

\(=\frac{2008b^2c+2008a^2c+2008a^2b-2008bc^2-2008a^2c-2008ab^2}{abc\left(a-b\right)\left(b-c\right)\left(a-c\right)}\)

\(=\frac{2008\left[\left(c^2a-c^2b\right)+\left(a^2b-a^2c\right)+\left(b^2a-b^2c\right)\right]}{abc\left(a-b\right)\left(b-c\right)\left(a-c\right)}\)

\(=\frac{2008\left(a-b\right)\left(b-c\right)\left(a-c\right)}{abc\left(a-b\right)\left(b-c\right)\left(a-c\right)}\)

\(=\frac{2008}{abc}\) ( với \(abc\ne0\))

a, = -a+b-c-c+a=b-2c

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

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

a) -(a-b+c)-(c-a) 

= - a + b - c - c +a 

= b - 2c

b)b-(b+a-c)

= b - b - a + c

= c - a

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

= a + b - a -  c

= b -  c

Học tót

 a) (x+17)-(24+35)      

= x+17 -24 -35

= x-42

b)  (-32)-(y+20)+20

=-32 - y -20 +20

= -32-y

c)  (a+b-c)-(b-c+d)   

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

= a-d

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

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

= c+d

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

= a+b +a - b+c 

= c

   f) -(a+b)+(a+b+c)

= a -b +a +b+c

= c