bo dau ngoac roi thu gon bieu thuc
a( b-c ) - c(b-d) +a(c+d) +bc
Bo dau ngoac roi rut gon bieu thuc :
a) - ( -a + c - d ) - ( c- a + d )
b) - ( a + b - c + d ) + ( a - b - c - d )
c) a( b- c -d ) - a( b + c - d )
Giup minh nhe minh dang can gap
a)= a-c+d-c+a-d
=2a-2c=2(a-c)
b)=-a-b+c-d+a-b-c-d
=-2b-2d
=2.(-b)-2d=2(-b-d)
c)=ab-ac-ad-ab-ac+ad
=-2.ac
Gấp đến mức độ nào vậy . Bài này đơn giản mà
Bo dau ngoac va thu gon bieu thuc:
a) (a+b)(2a+b)
b) (2a-b)(a-b)
c) (2a+b)(2a-b)
Bo dau ngoac roi rut gon bieu thuc :
A= a .( 5-b) + b . ( a- 5) - (5a + 3b )
B = ( x-1 ) . (x-2) - ( x2 + x + 8 )
Bo dau ngoac roi rut gon bieu thuc :
a) - ( - 12 + 25 - 36 ) - ( 12 - 36 + 57 )
b) - ( 23 + 5 - 6 + 17 ) + ( 23 - 5 - 83 - 6 )
c) 12 . ( 6 - 7 - 8 ) - 10 . ( 11 + 12 - 13 )
Giup minh voi minh dang can rat gap
a. = 12 - 25 + 36 - 12 + 36 - 57
= (12 - 12) + (36 + 36) - (25 + 57)
= 0 + 72 - 82
= -10
b. = -23 - 5 + 6 - 17 + 23 - 5 - 83 - 6
= (-23 + 23) + (-5 - 5) + (6 - 6) - (17 + 83)
= 0 + (-10) + 0 - 100
= -110
c.?
thu gon roi tinh bieu tri cua bieu thuc;
d=(10-a+b)-(10-b+c)-(10-c-a)
D=(10-a+b)-(10-b+c)-(10-c-a)
D= 10-a+b-10+b-c-10+c+a
D=(10-10-10)-(a-a)+(b+b)-(c-c)
D= -10+2b
Bo dau ngoa ri thu gon bieu thuc
A=(a+b)-(a-b)+(a-c)-(a+c)
B=(a+b-c)+(a-b+c)-(b+c-a)-(a-b-c)
Ta có
+> A = (a+b) - (a-b) + (a-c) -(a+c)
= a+b-a+b+a-c-a-c
= (a-a+a-a) + (b+b) - (c+c)
= 2b-2c
= 2(b-c)
+> B = (a+b-c) + (a-b+c) - (b+c-a) - (a-b-c)
= a+b-c+a-b+c-b-b+a-a+b+c
= (a+a+a-a) + (b-b-b-b+b) + (-c+c+c)
= 2a - b + c
Bo dau ngoa ri thu gon bieu thuc
A=(a+b)-(a-b)+(a-c)-(a+c)
B=(a+b-c)+(a-b+c)-(b+c-a)-(a-b-c)
A = a + b - a + b + a - c - a - c = (a - a + a - a) + (b + b) + (-c - c) = 2b - 2c = 2.(b - 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) = 2a
Bo ngoac roi rut gon:-a-(b-a-c)
don gian bieu thuc khi bo ngoac
-(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+0+0
=0