Sửa đề: B=-2x^2+xy+2y^2-3-5x+2y

a: A+B+C

=x^2-3xy-y^2+2x-3y+1-2x^2+xy+2y^2-3-5x+2y+C

=-x^2-2xy+y^2-3x-y-2+3x^2+7y^2-4xy-6x+4y+5

=2x^2+8y^2-6xy-9x+3y+3

b: 7A-B-C-9

=7A-9-(x^2+9y^2-3xy-11x+6y+2)

=7x^2-7y^2-21xy+14x-21y+7-x^2-9y^2+3xy-11x-6y-2-9

=6x^2-16y^2-18xy+3x-27y-4

c) (xy-1).(xy+5)

= x²y²+5xy-xy-5

=x²y²+4xy-5

a) b) d) bạn có thể ghi rõ được ko

A+B = \(4x^2y^3+6xy-7+\left(-8-3xy-3x^2y^3\right)\)

A+B = \(4x^2y^3+6xy-7-8-3xy-3x^2y^3\text{=}x^2y^3-3xy-15\)

A-B = \(7x^2y^3+9xy+1\)

B-A = \(-7x^2y^3-9xy-1\)

Câu bc mình ghi nhầm nên dừng làm

kết bạn với mình đi

hihihihihihhihihhihihihhihihihhihihhihi

Bài 2:

\(M=x^2-2xy+y^2=\left(x-y\right)^2=\left(-3\right)^2=9\)

\(N=x^2+y^2=\left(x-y\right)^2+2xy=9+2.10=29\)

\(P=x^3-3x^2y+3xy^2-y^3=\left(x-y\right)^3=\left(-3\right)^3=-27\)

\(Q=x^3-y^3=\left(x-y\right)^3+3xy\left(x-y\right)=\left(-3\right)^3+3.10.\left(-3\right)=-117\)

Bài 1:

a)  \(A=x^2+2xy+y^2=\left(x+y\right)^2=\left(-1\right)^2=1\)

b)  \(B=x^2+y^2=\left(x+y\right)^2-2xy=\left(-1\right)^2-2.\left(-12\right)=25\)

c)  \(C=x^3+3x^2y+3xy^2+y^3=\left(x+y\right)^3=\left(-1\right)^3=-1\)

d)  \(D=x^3+y^3=\left(x+y\right)^3-3xy\left(x+y\right)=\left(-1\right)^3-3.\left(-12\right).\left(-1\right)=-37\)

a: \(M=x^3+x^2-y^3+y^2+xy-3xy-95\)

\(=\left(x-y\right)^3+\left(x-y\right)^2-95\)

\(=7^3+7^2-95=297\)

b: \(N=3\left[\left(x+y\right)^2-2xy\right]-2\left(x+y\right)+6xy-100\)

\(=3\cdot\left(25-2xy\right)-10+6xy-100\)

=75-6xy-10+6xy-100

=-35