a/ 38+59-148-38+59=(38-38) + (59+59) -148=118-148=-30
b/43-245+69-43-69=(43-43)-245+(69-69)=-245
c/ {1260+420-620}-1260-420-280=1260+420-620-1260-420-280=(1260-1260)+(420-420)-(620+280)=-900
tạm bài 1 vì fải đi ngủ rùi
2) Thu gọn biểu thức:
a) -(2a-4b+c)-(-a-b+2c)
b)-(-4x+2y-62)+(4x+2y+48)
c)-(a-b-c+d)-(-a-b+c-d)-(a-2b)
1)Thu gọn biểu thức
a) -(2a-4b+c)-(-a-b+2c)
b) -(-4x+2y-62)+(4x+2y+48)
c) -(a-b-c+d)-(-a-b+c-d)-(a-2b)
LÀM GIÚP MK NHOA M.NG!mƠN NẠ
3. Bỏ ngoặc rồi tính :
a, 10 - ( 12 - ( -9 -1 ) )
b, ( 38 -29 + 43 ) - ( 43 + 38 )
c, 271 - ( (-43 ) + 271 - ( -17 ) )
d, -144 - ( 29 - ( + 144 ) - ( + 144 )
bỏ dấu ngoặc rồi thu rọn
-[-a-(-b)-c]-(a+b)+c
(2x+y)-(-2x+3y)+y
(a+2b+c)-(-a-2b-2c)-(4b+2a+c)-a-c
Phá ngoặc rồi viết gọn
1 , a - ( a - b - c ) - ( b - c -a ) - ( c - b -a )
2 , - ( a + b + c ) - ( b - c -a ) + ( 1 - a - b ) - ( c - 3b )
3 , ( b - c - 6 ) - ( 7 - a + b ) + c
4 , - ( 3b - 2a - c ) - ( a - b - c ) - ( a - 2b -+ 2c )
5 , ( 4a - 3b + 2c ) - ( 4b - 3c - 2a ) - ( 4c - 3a + 2b ) + ( a - b ) - c
6, 2a - { a - b [ a - b - ( a + b + c ) + 2b ] - c - b }
Phá ngoặc rồi viết gọn
1 , a - ( a - b - c ) - ( b - c -a ) - ( c - b -a )
2 , - ( a + b + c ) - ( b - c -a ) + ( 1 - a - b ) - ( c - 3b )
3 , ( b - c - 6 ) - ( 7 - a + b ) + c
4 , - ( 3b - 2a - c ) - ( a - b - c ) - ( a - 2b -+ 2c )
5 , ( 4a - 3b + 2c ) - ( 4b - 3c - 2a ) - ( 4c - 3a + 2b ) + ( a - b ) - c
6, 2a - { a - b [ a - b - ( a + b + c ) + 2b ] - c - b }
Phá ngoặc rồi viết gọn
1 , a - ( a - b - c ) - ( b - c -a ) - ( c - b -a )
2 , - ( a + b + c ) - ( b - c -a ) + ( 1 - a - b ) - ( c - 3b )
3 , ( b - c - 6 ) - ( 7 - a + b ) + c
4 , - ( 3b - 2a - c ) - ( a - b - c ) - ( a - 2b -+ 2c )
5 , ( 4a - 3b + 2c ) - ( 4b - 3c - 2a ) - ( 4c - 3a + 2b ) + ( a - b ) - c
6, 2a - { a - b [ a - b - ( a + b + c ) + 2b ] - c - b }
Phá ngoặc rồi viết gọn
1 , a - ( a - b - c ) - ( b - c -a ) - ( c - b -a )
2 , - ( a + b + c ) - ( b - c -a ) + ( 1 - a - b ) - ( c - 3b )
3 , ( b - c - 6 ) - ( 7 - a + b ) + c
4 , - ( 3b - 2a - c ) - ( a - b - c ) - ( a - 2b -+ 2c )
5 , ( 4a - 3b + 2c ) - ( 4b - 3c - 2a ) - ( 4c - 3a + 2b ) + ( a - b ) - c
6, 2a - { a - b [ a - b - ( a + b + c ) + 2b ] - c - b }
Bỏ dấu ngoặc rồi tính
a ) 159 − 524 − 59 − 424 ; b ) 36 + 79 + 145 − 79 − 36 ; c ) 334 − 117 + 234 + 42 + 117 ; d ) 271 − − 43 + 271 − − 17 .
