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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😧
![](https://rs.olm.vn/images/avt/0.png?1311)
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) \(-\left(a-b-c\right)-\left(a+b+c\right)=-a+b+c-a-b-c=-2a\)
![](https://rs.olm.vn/images/avt/0.png?1311)
#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 )
\(D=-a+b-c-a-b+c\)
\(D=-2a\)
![](https://rs.olm.vn/images/avt/0.png?1311)
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
![](https://rs.olm.vn/images/avt/0.png?1311)
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
![](https://rs.olm.vn/images/avt/0.png?1311)
( 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
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
-a-(b-a-c)
=-a-b+a+c
=[-a+a]-b+c
=0-b+c
=-b+c
-(a-c)-(a-b+c)
=-a+c-a+b-c
=0+0+b
=b
b-(b+a-c)
=b-b-a+c
=0-a+c
=-a+c
(a-b+c)-(a+b+c)
=a-b+c-a-b-c
=[a-a]+[c-c]-b-b
=0+0-b-b
=0-b-b
=-b-b
a) -a - ( b - a - c )
= -a - b + a + c
= ( -a + a ) -b + c
= 0 - b + c
= -b + c
b) - ( a - c ) - ( a - b + c )
= -a + c - a + b - c
= ( -a - a ) + ( c - c ) + b
= 2 . ( -a ) + b
c) b - ( b + a - c )
= b - b - a + c
= 0 - a + c
= -a + c
d) ( a - b + c ) - ( a + b + c )
= a - b + c - a - b - c
= a + ( -b ) + c + ( -a ) + ( -b ) + ( -c )
= [ a + ( -a ) ] + [ ( -b ) + ( -b ) ] + [ c + ( -c ) ]
= 0 + 2 . ( -b ) + 0
= 2 . ( -b )
\(\left(a-b+c\right)-\left(a-b+c\right)\)
\(=a-b+c-a+b-c\)
\(=\left(a-a\right)+\left(-b+b\right)+\left(c-c\right)=0\)
\(-\left(a-b-c\right)+\left(a-b-c\right)\)
\(=-a+b+c+a-b-c\)
\(=\left(-a+a\right)+\left(b-b\right)+\left(c-c\right)=0\)
\(\left(a+b-c\right)-\left(b-c+d\right)\)
\(=a+b-c-b+c-d\)
\(=a+\left(b-b\right)+\left(-c+c\right)-d=a-d\)
\(\left(a-b+c\right)-\left(a-d+c\right)\)
\(=a-b+c-a+d-c\)
\(=\left(a-a\right)+\left(c-c\right)+d-b=d-b\)
\(-\left(a-b-c\right)+\left(a-b+c\right)\)
\(=-a+b+c+a-b+c\)
\(=\left(-a+a\right)+\left(b-b\right)+\left(c+c\right)=2c\)
Ủng hộ mk nha !!! ^_^