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 )
d)(a+ b) ( c + d) – ( a + d ) ( b + c ) e)( a + b ) ( c – d ) – ( a – b ) ( c + d ) f) ( a + b ) ^2 – ( a – b )^2
Bỏ ngoặc rồi rút gọn biểu thức:
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 ) ; d)(a+ b) ( c + d) – ( a + d ) ( b + c )
e)( a + b ) ( c – d ) – ( a – b ) ( c + d ) ; f) ( a + b ) 2 – ( a – b ) 2
a) - ( - a + c – d ) – ( c – a + d )
= a - c - d - c + a + d
= (a + a) + (-c - c) + (-d + d)
= 2a - 2c
b) – ( 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 - 2d
a) - ( - a + c - d) - ( c - a + d )
= a - c + d - c + a - d
= 2a
b) - ( a+ b - c + d ) + ( a -b -c -d )
= - a-b+c-d+a-b-c-d
=-2d -2b
c) a(b-c-d) - a(b+c-d)
= a(b-c-d-b-c+d)
= ab-ac-ad-ab-ac+ad
= -2ab-2ac
d) (a+b)(c+d)-(a+d)(b+c)
= ac+ad+bc+bd - (ab+ac+bd+cd)
= ac+ad+bc+bd-ab-ac-bd-cd
=ad+bc-ab-cd
a) - ( - a + c - d) - ( c - a + d )
= a - c + d - c + a - d
= 2a
b) - ( a+ b - c + d ) + ( a -b -c -d )
= - a-b+c-d+a-b-c-d
=-2d -2b
c) a(b-c-d) - a(b+c-d)
= a(b-c-d-b-c+d)
= ab-ac-ad-ab-ac+ad
= -2ab-2ac
d) (a+b)(c+d)-(a+d)(b+c)
= ac+ad+bc+bd - (ab+ac+bd+cd)
= ac+ad+bc+bd-ab-ac-bd-cd
=ad+bc-ab-cd
e)(a+b)(c-d)-(a-b)(c+d)
= ac-ad+bc-bd-ac-ad+bc+bd
= 2bc-2ad
f) ( a + b )2 – ( a – b )2
= a2+2ab+b2 - (a2+2ab-b2)
=a2+2ab+b2 - a2-2ab+b2
=2b2
Bài 1: bỏ dấu ngoặc rồi rút gọn biểu thức a, - ( - a + c - d ) - ( c - d + d) b, - ( a + b - c + d ) + (a - b - c - d) c, a( b - c - d ) - a( b + c -d ) d*, (a + b).(c+d) - ( a+d).(b+c) e*, (a+b).(c-d) - (a-b).(c+d) f*, (a+b)2 - (a-b)2
a, -( -a + c - d) - ( c - d + d) = a - c + d - c + d - d = a + d
b, - ( a+b-c+d) + (a-b-c-d) = -a -b+c-d + a-b-c-d = -2b + (-2c)= -2(b+c)
a/b = c/d=e/f CMR:
a) a/b=c/d=e/f=a+c+e/b+d+f
b) a/b=c/d=e/f =a-c+e/b-d+f
c) a/b=c/d=e/f =a-c-e/b-d-f
Bỏ dấu ngoặc rồi rút gọn biểu thức:
a) - ( - a + c - d) - (c - a + d )
b) - (a + b - c + d) + ( a - b - c -d )
c) ( a + b - c ) - ( b - c + d)
d) ( b + a) + ( c - d) - (c +a ) - ( b - d)
e) ( a - b) - ( d + a) - (c - d) + ( c + b)
f) - a + ( c- b ) - (c + a - b)
a) -(-a + c - d) - (c - a + d) = a - c + d - c + a - d = (a + a) - (c + c) + (d - d) = 2a - 2c
b) -(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 - 2d
c) (a + b - c) - (b - c + d) = a + b - c - b + c - d = a + (b - b) - (c - c) - d = a - d
d) (b + a) + (c - d) - (c + a) - (b - d) = b + a + c - d - c - a - b + d = (b - b) + (a - a) + (c - c) - (d - d) = 0
e) (a - b) - (d + a) - (c - d) + (c + b) = a - b - d - a - c + d + c + b = (a - a) - (b - b) - (d - d) - (c - c) = 0
f) -a + (c - b) - (c + a - b) = - a + c - b - c - a + b = (-a - a) + (c - c) - (b - b) = -2a
a ) a - c + d - c + a - d = 2a - 2c
b ) -a - b + c - d + a - b - c - d = -2b - 2d
CÁC CÂU CÒN LẠI LÀM TƯƠNG TỰ NHÉ!!
a) - ( -a + c - d ) - ( c - a + d ) = a - c + d - c + a - d = ( a + a ) - ( c + c ) + ( d - d ) = 2a - 2c = 2 ( a - c )
b) - ( 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
c) ( a + b - c ) - ( b - c + d ) = a + b - c - b + c - d = a + ( b + b ) - ( c - c ) - d = a + 2b -d
d) ( b + a ) + ( c - d ) - ( c + a ) - ( b - d ) = b + a + c - d - c - a - b + d = ( b - b ) + ( a - a ) + ( c - c ) - ( d - d ) = 0
e) ( a - b ) - ( d + a ) - ( c - d ) + ( c + b ) = a - b - d - a - c + d + c + b = ( a - a ) - ( b - b ) - ( d - d ) - ( c - c ) = 0
f) -a + ( c - b ) - ( c + a - b ) = -a + c - b - c - a + b = ( -a - a ) + ( c - c ) - ( b - b ) = -2a
=))
Từ tỉ lệ thức a/b = c/d ( a,b,c,d khác 0 ; a khác + - b ; c khác + - d ) hãy suy ra các tỉ lệ thức sau
a ) a + b / b = c + d / d
b ) a - b /b = c - d /d
c ) a + b / a = c + d / c
d ) a - b /a = c - d / c
e ) a / a + b = c / c + d
f ) a / a - b = c / c - d
Bỏ dấu ngoặc rồi rút gọn biểu thức
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)
d*) (a+b)(c+d0-(a+d)(b+c)
e*) (a+b)(c-d)-(a-b)(c+d)
f*) (a+b)^2-(a-b)^2
Bỏ dấu ngoặc rồi rút gọn biểu thức
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)
d*) (a+b)(c+d0-(a+d)(b+c)
e*) (a+b)(c-d)-(a-b)(c+d)
f*) (a+b)^2-(a-b)^2
a)-(-a+c-d)-(c-a+d)=a-c+d-c+a-d=(a+a)-(c+c)+(d-d)=2a-2c=2(a-c)
b)-(a+b-c+d)+(a-b-c-d)=-a-b+c-d+a-b-c-d=(-a+a)-(b+b)+(c-c)-(d+d)=0-2b+0-2d=-2(b-d)
c)a(b-c-d)-a(b+c-d)=ab-ac-ad-ab-ac+ad=(ab-ac)-(ac+ac)-(ad-ad)=2ac
d)đề sai
e)(a+b)(c-d)-(a-b)(c+d)=ac+b-ad+b-(ac-b+ad-b)=ac+b-ad+b-ac+b-ad+b=(ac-ac)+(b+b+b+b)-(ad+ad)=4b-2ad=2(2b-ad)
f)(a+b)2-(a-b)2=a2+2ab+b2-(a2-2ab+b2)=a2+2ab+b2-a2+2ab-b2=(a2-a2)+(2ab+2ab)+(b2-b2)=4ab
mk k chắc đâu
-(a+b-c)+(b+c-d)-(c+d-a)
Biến đổi vế trái thành phải
a) a (b-c) + c (a-b) = b (a-c)
b) a(b-c) -b (a+c) = (a+b) -(-c)
c) a (b+c) - b (a-c) = (a+b) c
d) a (b-c) - a(b+d) = a (c+d)
e) (a-b) (c+d) - (a+d) (b+c)= (a-c) (d-b)
a) a(b-c)+c(a-b)=ab-ac+ca-cb=ab-cb=b(a-c)
b) a(b-c)-b(a+c)=ab-ac-ab-bc=-ac-bc=-c(a+b)
c) a(b+c)-b(a-c)=ab+ac-ab+bc=ac+bc=c(a+b)
d) a(b-c)-a(b+d)=ab-ac-ab-ad=-ac-ad=-a(a+d)
a) a(b - c) + c(a - b) = ab - ac + ac - bc = ab - bc = b(a - c)
b) a(b - c) - b(a + c) = ab - ac - ab - bc = -ac - bc = (a + b). (-c)
c) a(b + c) - b(a - c) = ab + ac - ab + bc = ac + bc = (a + b)c
d) a(b - c) - a(b + d) = ab - ac - ab - ad = -ac - ad = -a(c + d)
a) a(b-c)+c (a-b)=ab-ac+ca-cb=cb=b(a-c)
b) a(b-c)-b(a+c)=ab-ac-ab-bc=ac-bc=-c(a+b)
c) a(b+c)-a(b(a-c)=ab+ac-ab+bc=ac+bc=c(a+b)
d) a(b-c)-a(b+d)=ab-ac-ab-ad=ac-ab-ad=ac-ad=a(a+d)
Từ tỉ lệ thức a/b=c/d hãy suy ra các tỷ lệ thức sau
A) a-b/a=c-d/c
B) a/a-b=c/c-d
C) a+b/b=c+d/d
D) a+b/a=c+d/c
E) a/a+b=c/c+d