a, \(\left(-a\right)\left(b-c-d\right)=-ab+ac+ad\)

b, \(x\left(y-z-2\right)=xy-xz-2x\)

c, \(\left(-3\right)\left(2x-5\right)=-6x+15\)

a)(x+y).(x+y)=x(x+y)+y(x+y)=x^2+xy+xy+y^2=x^2+2xy+y^2

b)(x-y).(x-y)=x(x-y)-y(x-y)=x^2-xy-xy+y^2=x^2-2xy+y^2

c)(x+y).(x-y)=x(x-y)+y(x-y)=x^2-2xy+xy-y^2=x^2-y^2

nhớ liek nhé

a ,  = \(x^2+2xy+y^2\)

b, = \(x^2-2xy+y^2\)

c = \(x^2-y^2\)

Bỏ dấu ngoặc rồi thu gọn biểu thức sau:

a) (a+b)-(a-b)+(a-c)-(a+c)

=a+b-a+b+a-c-a-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-c+a-a+b+c

=3a+3b-3b

=3(a+b-c)

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.

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

=(a+a+a-a)+(b-b-b+b)+(-c+c-c+c)

=2a

a, A =(a-2b+c)-(a-2b-c)

   A = a-2b+c-a+2b+c

   A = 0

b, B = (-x-y+3)-(-x+2-y)

   B = -x-y+3+x-2+y

   B = 1

c, C = 2.(3a+b-1)-3.(2a+b-2)

   C = 6a+2b-2-6a-3b+6

   C = -b + 4

d, D = 4.(x-1)-(3x+2)

    D = 4x-4-3x-2

    D = x-6

\(a.\left(-x+y\right)-\left(z+y-x\right)=-x+y-z-y+x=-z\)

\(b.\left(a-b\right)-\left(x-b+a\right)=a-b-x+b-a=-x\)

Các câu còn lại tương tự

a) (-x+y)-(z+y-x)=-x+y-z-y+x=(-x+x)+(y+-y)-z=-z

b) (a-b)-(x-b+a)=a-b-x+b-a=(a+-a)+(-b+b)-x=-x

c) -(x+y)+(x-y+m)-(m-y)=-x-y+x-y+m-m+y=(-x+x)+(-y+-y+y)+(m-m)=y

d) -(a+b-c)+(a+b-m)-(c-m)=-a-b+c+a+b-m-c+m=(-a+a)+(-b+b)+(-m+m)-c=-c

a) 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 )

= 0 + 2b + 2(-c)[ - c - c = -c + ( -c )]

= 2b + 2(-c)

=2(b - c )(= 2 . [ b + ( - c ) ]  )

b) B = ( a + b - c ) + ( a - b + c )- ( b + c - a ) - ( a - b - c )

   B = a + b - c + a - b + c - b - c + a - a + b + c

   B = ( a + a + a - a ) + ( b - b - b + b ) + ( -c + c - c + c )

   B = 2a + 0 + 0

   B = 2a

a,A=a+b-a+b+a-c-a-c

=2b-2c-a

b,B=a+b-c+a-b+c-b-c+a-a+b+c

=2a+0b+0c

Bài 2:

a. -(-a+c-d) - (c-a+d)

= a-c+d-c+a-d

= 2a-2c

b. -(a+b-c+d) + (a-b-c-d)

= -a-b+c-d+a-b-c-d

= -2b-2d

c. a(b-c-d) - a(b+c-d)

= a. [(b-c-d) - (b+c-d)]

= a.(b-c-d-b-c+d)

= a.(-2c)

=-2ac

Mk ko chắc là đúng đâu

a) (a+b)-(a-b)+(a-c)-(a+c)

= a + b - a + b - a + c - a - c

= ( a - a ) + ( b + b ) + ( -a-a) + ( c - c )

= 0 + 2b + (-2a )+ 0

= 2b + (-2a)

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

= ( a - a ) + ( b - b ) + ( -c + c ) + ( a + a ) + ( - b + b ) + ( -c+c)

= 0 + 0 + 0 + 2a + 0 + 0

= 2a

Nhớ k cho mk nha

a,(a+b)-(a-b)+(a-c)-(a+c)

=a+b-a+b+a-c-a-c

=2b

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