Thu gọn: (a + b + c) + (a - b)-(a - b + c)
Thu gọn các tổng sau:
a) (a - b + c - d) - (a + b + c + d)
b) (-a + b - c) + (a - b) - (a - b + c)
\(a,=a-b+c-d-a-b-c-d=-2b-2d\\ b,=-a+b-c+a-b-a+b-c=-a+b-2c\)
a) ( a - b + c -d ) - ( a+ b + c + d ) = a - b + c - d - a - b - c - d = -2b - 2d
b) ( -a + b -c ) + ( a - b ) - ( a- b + c ) = -a + b - c + a - b - a + b - c = -a + b - c - c = -a + b - 2c
c) - ( a - b - c ) + ( b - c + d ) - ( -a + b + d )
Thu gọn biểu thức sau
a) A = ( a+ b – c + d ) – ( - a – b + c – d );
b) B= ( a+ b –c ) + ( a –b ) – ( a – b - c ).
a) A = ( a+ b – c + d ) – ( - a – b + c – d )
= a+ b – c + d + a + b - c + d
= 2a + 2b + 2d – 2c
b) B = ( a+ b – c ) + ( a – b ) – ( a – b - c )
= a+ b – c + a – b – a + b + c
= a + b
Thu gọn biểu thức: a. (a – b – d) + (b – a + d)
b. – (a – b + c) – (a – b – c)
c. (c – a + d) + (a – b – d)
Thu gọn các tổng sau:
a) (a –b + c- d) – ( a+ b-+c+d)
b) ( -a + b – c) + ( a – b) – (a – b + c)
c) – ( a- b- c) + ( b – c+d) – ( a-b +c)
a) (a - b + c - d) - (a + b - + c + d) = a - b + c - d - a - b + c - d = -2b + 2c - 2d
b) (-a + b - c) + (a - b) - ( a - b + c) = -a + b - c + a - b - a + b - c = -a + b - 2c
c) -(a - b - c) + (b - c + d) - (a - b + c) = -a + b + c + b - c + d - a + b - c = -2a + 3b - c + d
`@` `\text {Ans}`
`\downarrow`
`a)`
`(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 + 2c - 2d`
`b)`
` ( -a + b - c) + ( a - b) - (a - b + c)`
`= -a + b - c + a - b - a + b - c`
`= (-a +a - a) + (b - b + b) + (-c-c)`
`= a + b - 2c`
`c)`
\( – ( a- b- c) + ( b – c+d) – ( a-b +c)\)
`= - a + b + c + b - c + d - a + b - c`
`= (-a -a) + (b + b + b) + (c-c-c) + d`
`= -2a + 3b - c + d`
Thu gọn biểu thức sau:
B = (a + b - c) + ( a - b) - (a - b - c)
B = ( a+ b – c ) + ( a – b ) – ( a – b - c )
= a+ b – c + a – b – a + b + c = a + b
Thu gọn:
-(a-b-c)+(-a+b-c)-(-a-b-c)
= -a + b + c - a + b - c + a + b +c
= -a +3b + c
-(a - b - c) + (-a + b - c) - (-a - b - c)
= -a + b + c - a + b - c + a + b + c
= (-a + a + a) + (b + b + b) + (-c + c + c)
= a + 3b + c
\(-(a-b-c)+(-a+b-c)-(-a-b-c)\)
\(=-a+b+c+(-a)+b-c+a+b+c\)
\(=-a+b+c-a+b-c+a+b+c\)
\(=(-a-a+a)+(b+b+b)+(c-c+c)\)
\(=-a+3b+c\)
~ Học tốt a~
B1:bỏ ngoặc rồi rút gọn các biểu thức sau:
a,(a+b)-(a-b)+(a-c)-(a+c)
b, (a+b-c)+(a-b+c)-(b+c-a)-(a-b-c)
B2:xét biểu thức N= -{-(a+b)-[(a-b)-(a+b)]}
bỏ ngoặc và thu gọn
B1:
a, a+b+(-a)+b+a+(-c)+(-a)+(-c)=[a+(-a)+a+(-a)]+(b+b)+[(-c)+(-c)]=0+2.b+(-2).c
b, a+b+(-c)+a+(-b)+c+(-b)+(-c)+a+(-a)+b+c=[a+a+a+(-a)]+[b+(-b)+(-b)+b]+[(-c)+c+(-c)+c]=2.a+0+0=2a
B2:
N=(a+b)-(a-b)+(a+b)=a+b+(-a)+b+a+b=[a+(-a)+a)+(b+b+b)=a+3.b
NẾU CẬU KHÔNG HIỂU THÌ CỨ HỎI NHÉ!
rút gọn biểu thức
a,A=(a-b)-(a-b+c)
b,B=-(a+b+c)-(a+b-5)
Thu gọn : C = a ( b + c ) - b ( a - c ) - c ( a + b ) + 3 ac
Ta có: C = a (b + c) - b (a - c) - c (a + b) + 3 ac
= ab + ac - ba + bc - ca - cb + 3 ac
= (ab - ba) + (ac - ca) + (bc - cb) + 3 ac
= 0 + 0 + 0 + 3 ac
= 3 ac
bài 6 : Bỏ dấu ngoặc rồi thu gọn biểu thức :
a) A= (a+b) - (a-b) + (a-c) - (a+c) b) B= (a+b-c) + (a-b+c) - (b+c-a) - (a-b-c)
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) \(B=\left(a+b-c\right)+\left(a-b+c\right)-\left(b+c-a\right)-\left(a-b-c\right)\)
\(B=a+b-c+a-b+c-b-c+a-a+b+c\)
\(B=\left(a+a+a-a\right)+\left(b-b-b+b\right)+\left(-c+c-c+c\right)\)
\(B=2a+0+0\)
\(B=2a\)