Question

cần gấp

Answer 1

2.20:

a: \(A=\left(a-2\right)^2-\left(2-a\right)\)

\(=\left(2-a\right)^2-\left(2-a\right)\)

=(2-a)(2-a-1)

=(2-a)(1-a)

b: \(B=8x\left(x-y\right)-6y\left(y-x\right)\)

=8x(x-y)+6y(x-y)

=(x-y)(8x+6y)

=2(4x+3y)(x-y)

c:Sửa đề: \(C=x\left(x-y\right)-2x+2y\)

=x(x-y)-2(x-y)

=(x-y)(x-2)

d: \(D=16x^2\left(x-y\right)-10x\left(y-x\right)\)

\(=16x^2\left(x-y\right)+10x\left(x-y\right)\)

\(=\left(x-y\right)\left(16x^2+10x\right)=2x\left(8x+5\right)\left(x-y\right)\)

Bài 2.21:

a: \(A=a\left(b-3\right)+b\left(3-b\right)+\left(3-b\right)\)

=a(b-3)-b(b-3)-(b-3)

=(b-3)(a-b-1)

b: \(B=\left(x+y\right)^3+x\left(x+y\right)^2=\left(x+y\right)^2\cdot\left(x+y+x\right)=\left(x+y\right)^2\cdot\left(2x+y\right)\)

c: \(C=a\left(a-b\right)^2-\left(b-a\right)^3\)

\(=a\left(a-b\right)^2+\left(a-b\right)^3\)

\(=\left(a-b\right)^2\cdot\left(a+a-b\right)=\left(2a-b\right)\left(a-b\right)^2\)

d:Sửa đề: \(D=2x\left(8x-4y\right)-3y\left(8x-4y\right)+4x-8y\)

=(2x-3y)(8x-4y)-(8x-4y)

=(8x-4y)(2x-3y-1)

=4(2x-y)(2x-3y-1)