A=ab(b²-a²)+(a+b)

=ab(a+b)(b-a)+(a+b)

=(a+b)(ab²-a²b+1)

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

\(=ab\left(a+b\right)b-a+\left(a+b\right)\)

\(=\left(a+b\right)\left(ab^2-a^2b+1\right)\)

~Hok tốt~

Bài làm:

1) Ta có: \(2x^2+5xy+2y^2\)

\(=\left(2x^2+4xy\right)+\left(xy+2y^2\right)\)

\(=2x\left(x+2y\right)+y\left(x+2y\right)\)

\(=\left(2x+y\right)\left(x+2y\right)\)

2) Ta có: \(2x^2+2xy-4y^2\)

\(=\left(2x^2-2xy\right)+\left(4xy-4y^2\right)\)

\(=2x\left(x-y\right)+4y\left(x-y\right)\)

\(=2\left(x+2y\right)\left(x-y\right)\)

\(1)2x^2+5xy+2y^2=2x^2+4xy+xy+2y^2=\left(2x^2+4xy\right)+\left(xy+2y^2\right)=2x\left(x+2y\right)+y\left(x+2y\right)=\left(2x+y\right)\left(x+2y\right)\)\(2)2x^2+2xy-4y^2=2x^2+4xy-2xy-4y^2=\left(2x^2-2xy\right)+\left(4xy-4y^2\right)=2x\left(x-y\right)+4y\left(x-y\right)=\left(2x+4y\right)\left(x-y\right)\)

A= a²(1-b²) - b(1-b) - a(1-b)

=a²(1-b)(1+b) - b(1-b) - a(1-b)

=(1-b)(a²+a²b-b-a)

=(1-b)[a(a-1) + b(a²-1)]= (1-b)[a(a-1) + b(a-1)(a+1) =(1-b)(a-1)(a+ab+b)

Chỗ nào ko hiểu thì hỏi nhé ^^

\(\left(ab+1\right)^2-\left(a+b\right)^2=\left(ab+1+a+b\right)\left(ab+1-a-b\right).\)

\(=\left(a+1\right)\left(b+1\right)\left(a-1\right)\left(b-1\right)\)

\\(x^2-2x-4y^2-4y=\left(x^2-2x+1\right)-\left(4y^2+4y+1\right)=\left(x-1\right)^2-\left(2y+1\right)^2\)

\(=\left(x+1+2y+1\right)\left(x+1-2y-1\right)=\left(x+2y+2\right)\left(x-2y\right)\)

a, \(a+2\sqrt{ab}+b=\left(\sqrt{a}+\sqrt{b}\right)^2\)

b,\(x^2+2xy+y^2+x^2-y^2=\left(x+y\right)^2+\left(x-y\right)\left(x+y\right)\)\(=\left(x+y\right)\left(x+y+x-y\right)=2x\left(x+y\right)\)

-(bc^2-ac^2-b^2c-a^2c+ab^2-a^2b)

Ta có : \(A=ab(a-b)+bc(b-c)+ca(c-a)\)

\(\Rightarrow A=ab(a-b)-bc(c-b)+ac(c-a)\)

\(\Rightarrow A=ab(a-b)-bc[(c-a)+(a-b)]+ac(c-a)\)

\(\Rightarrow A=ab(a-b)-bc(a-b)-bc(c-a)+ac(c-a)\)

\(\Rightarrow A=(a-b)(ab-bc)+(c-a)(ac-bc)\)

\(\Rightarrow A=b(a-b)(a-c)-(a-c)c(a-b)\)

\(\Rightarrow A=(a-c)(a-b)(b-c)\)

Chúc học tốt trong kì thi tới :>