Thu gọn
a. A=(a+b+c-d)-(a-b+c-d)+a
b. B=-(a-b-d)+(b-c+d)-(-c+b+d)
c. C=(a-b)-(c-d)+(b+c)
BÀI TOÁN: Bỏ dấu ngoặc và rút gọn
a) a(b-c+d)-ad;
b) (a-b)(c+d)+(-a+b)(c+d);
c) (a+b)(c+d)-(a-b)(c+d)
a: =ab-ac+ad-ad=ab-ac
b:=(c+d)(a-b-a+b)=0
các bạn giúp mình làm bài toán này nhé !
a: =ab-ac+ad-ad=ab-ac
b:=(c+d)(a-b-a+b)=0
HT
Rút gọn
a) (a-b-c)-(-c+b+a)-(a-b)
b)a(b+c)-a(b+d)-(1+ac-ad)
a: \(\left(a-b-c\right)-\left(-c+b+a\right)-\left(a-b\right)\)
\(=a-b-c+c-b-a-a+b\)
\(=-a-b\)
b: \(a\left(b+c\right)-a\left(b+d\right)-\left(1+ac-ad\right)\)
\(=ab+ac-ab-ad-1-ac+ad\)
=-1
1.Chứng minh các đẳng thức sau
a)(a+b+c)^2+(b+c-a)^2+(c+a-b)^2= 4(a^2+b^2+c^2)
b)(a+b+c+d)^2+(a+b+c-d)^2+(a+c-b-d)^2+(a+d-b-c)^2= 4(a^2+b^2+c^2+d^2)
c)(a^2-b^2-c^2-d^2)+2(ab-bc+cd+da)^2= (a^2+b^2+c^2+d^2)-2(ab-ad+bc+dc)^2
d)(a+b+c)^2+a^2+b^2+c^2= (a+b)^2+(b+c)^2=(c+a)^2
2. Chứng minh rằng
a) Nếu (a+b+c+d)(a-b-c+d)=(a-b+c-d)(a+b-c-d) thì a/b=c/d
b) Nếu (a+b+c)^2= 3(ab+bc+ca) thì a=b=c
1 Bỏ ngoặc tính rồi thu gọn;
a,(a+b+c+d)-(a-b+c-d)
b,(-a+b-c+d)+(a+d)+(-b+c)
c,-(a-b-d)+(b-c+d)-(-c+b-d)
a, \(\left(a+b+c+d\right)-\left(a-b+c-d\right)\)
\(=a+b+c+d-a+b-c+d=2b+2d\)
\(=2.\left(b+d\right)\)
b, \(\left(-a+b-c+d\right)+\left(a+d\right)+\left(-b+c\right)\)
\(=-a+b-c+d+a+d-b+c\)
\(=2d\)
c, \(-\left(a-b-d\right)+\left(b-c+d\right)-\left(-c+b-d\right)\)
\(=-a+b+d+b-c+d+c-b+d\)
\(=-a+b+3d\)
Chúc bạn học tốt!!!
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 + 2d = 2.(b + d)
b,(-a+b-c+d)+(a+d)+(-b+c) = -a + b - c + d + a + d - b + c = (-a + a) + (b - b) + ( -c + c) + (d + d) = 2d
c,-(a-b-d)+(b-c+d)-(-c+b-d)= -a + b + d + b - c + d + c - b + d = -a + (b + b - b) + (-c + c) + ( d + d + d) = -a + b + 3d
\(\left(a+b+c+d\right)-\left(a-b+c-d\right)\)
\(=a+b+c+d-a+b-c+d\)
\(=2b+2d\)
\(=2\left(b+d\right)\)
\(\left(-a+b-c+d\right)+\left(a+d\right)+\left(-b+c\right)\)
\(=-a+b-c+d+a+d-b+c\)
\(=2d\)
\(-\left(a-b-d\right)+\left(b-c+d\right)-\left(-c+b-d\right)\)
\(=-a+b+d+b-c+d+c+b-d\)
\(=-a+2b+d\)
Bỏ dấu ngoặc rồi 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+D)
( *¯ ³¯*)♡
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)
= 0 + 0 + 0 - 2d
= -2d
Ý b, c em xem lại xem sao chỗ chữ cái viết hoa chỗ lại viết thường là sao em nhỉ?
Cô oi chữ nó bị thế thoi, A và a giống nhau cô ah
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`
Phá ngoặc rồi thu gọn
1. a( b - c - d ) - a(b + c - d )
2. ( a + b) ( c + d ) - ( a + d) ( b + c)
3. ( a +b ) ( c - d ) - ( a- b) ( c + d )
1) \(a\left(b-c-d\right)-a\left(b+c-d\right)\)
\(=ab-ac-ad-ab-ac+ad\)
\(=-2ac\)
2) \(\left(a+b\right)\left(c+d\right)-\left(a+d\right)\left(b+c\right)\)
\(=ac+ad+bc+bd-ab-ac-bd-cd\)
\(=ad+bc-ab-cd\)
3) \(\left(a+b\right)\left(c-d\right)-\left(a-b\right)\left(c+d\right)\)
\(=ac-ad+bc-bd-ac-ad+bc+bd\)
\(=-2ad+2bc\)
\(=-2\left(ad-bc\right)\)
Thu gọn 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 + d )
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 )
a) (a-b+c-d)-(a+b+c+d)
=a-b+c-d-a-b-c-d
=-2b-2d
=2(b-d)
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+d)
=-a+b+c+b-c+d+a-b-d
=b