c,f  fk,l,xskooe

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

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

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

=a + 0 - c² - d

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

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

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

=0 + 0 - c + d

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

=-a - b + a + b - c

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

=0 - b² - c

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

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

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

=0 - b - c² + dd

Mỏi cả tay😧

1) Đơn giản biểu thức SAU khi bỏ dấu ngoặc:

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

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

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

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

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

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

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

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

a) \(-a-b+a+c=c-b\)

b) \(-a+c-a+b-c=b-2a\)

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

d)   \(-a+b-c-a-b-c=-2a-2c\)

#Trl :

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

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

\(A=-b+c\)

-------------------

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

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

\(B=-2a+b\)

--------------------

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

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

\(C=-a+c\)

-------------------

\(D=-\left(a-b+c\right)-\left(a+b-c\right)\)(đoạn này cậu đánh nhầm dấu ) thành số 0 nè )

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

\(D=-2a\)

1. 

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

2.

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

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

=1-a+b-c-a-b-c

=1-(a-a)+(b-b)-(c-c)

=1-0+0-0

=1

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

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

=2.2a+0+0

=2.2a

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

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

=a+d

mình ko hiểu có y/n j

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

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

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

= a + (-d) + 0 + 0

= a + (-d)

Chúc bạn hk tốt

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

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

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

=a+0+0-d=a-d

bài này dễ mà em (a-b+c)-(d+c-b)=a-b+c-d-c+b=a-d

\(\left(a-b+c\right)-\left(d+c-b\right)\)

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

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

\(=a-d\)

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

= a + c - a + b - c

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

= 0 + 0 + b

= b

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

= -a - b + a + c + b

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

= 0 + 2b + c

= 2b + c

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

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

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

= 0 + 0 + 0

= 0

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

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

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

= 0 + 2b + 2c

= 2b + 2c

e) (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 + 0 + 2c

= 2a + 2c

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

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

Tk mk nha

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

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

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

= 0+0+a-d

= a-d

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

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

= (a-a) + (b-b) - c + d

= 0 + 0 - c + d

= - c + d