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

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

a)-b+c

d)-2a-2c

e)2b-2c

b)-2a+b

c)-a+c

f)a

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

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

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

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

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

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

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

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

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

d) (b + a) + (c - d) - (c + a) - (b - d) = b + a + c - d - c - a - b + d = (b - b) + (a - a) + (c - c) - (d - d) = 0

e) (a - b) - (d + a) - (c - d) + (c + b) = a - b - d - a - c + d +  c + b = (a - a) - (b - b) - (d - d) - (c - c) = 0

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

a ) a - c + d - c + a - d = 2a - 2c 

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

 CÁC CÂU CÒN LẠI LÀM TƯƠNG TỰ NHÉ!!

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

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

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

d) ( b + a ) + ( c - d ) - ( c + a ) - ( b - d ) = b + a + c - d - c - a - b + d = ( b - b ) + ( a - a ) + ( c - c ) - ( d - d ) = 0

e) ( a - b ) - ( d + a ) - ( c - d ) + ( c + b ) = a - b - d - a - c + d + c + b = ( a - a ) - ( b - b ) - ( d - d ) - ( c - c ) = 0

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

=))

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

b)-(a+b-c+d)+(a-b-c-d)=-a-b+c-d+a-b-c-d=(-a+a)-(b+b)+(c-c)-(d+d)=0-2b+0-2d=-2(b-d)

c)a(b-c-d)-a(b+c-d)=ab-ac-ad-ab-ac+ad=(ab-ac)-(ac+ac)-(ad-ad)=2ac

d)đề sai

e)(a+b)(c-d)-(a-b)(c+d)=ac+b-ad+b-(ac-b+ad-b)=ac+b-ad+b-ac+b-ad+b=(ac-ac)+(b+b+b+b)-(ad+ad)=4b-2ad=2(2b-ad)

f)(a+b)²-(a-b)²=a²+2ab+b²-(a²-2ab+b²)=a²+2ab+b²-a²+2ab-b²=(a²-a²)+(2ab+2ab)+(b²-b²)=4ab

mk k chắc đâu

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

b) F=3.(b-c)-(a+c)+5.(a-b-c)

   F=3b-3c-a-c+5a-5b-5c

   F=(-a+5a)+(3b-5b)+(-3c-c-5c)

  F= 4a+(-2b)+(-9c)

  F=4a-2b-9c

a) E=2.(a+b)+3.(a-c)-4(b+c)

   E=2a+2b+3a-3c-4b-4c

   E=(2a+3a)+(2b-4b)+(-3c-4c)

   E=5a+(-2b)+(-7c)=5a-2b-7c

c)G=7.(a-b-c)+4.(b+c)-6(b-c-a)

G=7a-7b-7c+4b+4c-6b+6c+6a

G=(7a+6a)+(-7b+4b-6b)+(-7c+4c+6c)

G=13a+(-9b)+3c

G=13a-9b+3c

a) - ( - a + c – d ) – ( c – a + d ) 

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

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

= 2a - 2c               

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

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

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

= -2b - 2d

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

= a - c + d - c + a - d 

= 2a

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

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

=-2d -2b

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

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

= ab-ac-ad-ab-ac+ad

= -2ab-2ac

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

= ac+ad+bc+bd - (ab+ac+bd+cd)

= ac+ad+bc+bd-ab-ac-bd-cd

=ad+bc-ab-cd

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

= a - c + d - c + a - d 

= 2a

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

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

=-2d -2b

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

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

= ab-ac-ad-ab-ac+ad

= -2ab-2ac

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

= ac+ad+bc+bd - (ab+ac+bd+cd)

= ac+ad+bc+bd-ab-ac-bd-cd

=ad+bc-ab-cd

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

= ac-ad+bc-bd-ac-ad+bc+bd

= 2bc-2ad

f) ( a + b )² – ( a – b )²

= a²+2ab+b² - (a²+2ab-b²)

=a²+2ab+b² - a²-2ab+b²

=2b²

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ai tích mình

mình tích lại

thanks

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

 = 2c - a - b

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

 = -2a - 2c

c) - a - (b+c)

 = -a - b - c

d) -a.(b-a-c)

 = a² - ab + ac

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

 = 2b - 2c

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

 = 2a