Bài 1:
\(a,x^2-y^2-2x+2y=\left(x-y\right)\left(x+y\right)-2\left(x-y\right)=\left(x-y\right)\left(x+y-2\right)\)
\(b,2x+2y-x^2-xy=2\left(x+y\right)-x\left(x+y\right)=\left(2-x\right)\left(x+y\right)\)
\(c,3a^2-6ab+3b^2-12c^2=3\left(a-b\right)^2-12c^2=3\left[\left(a-b\right)^2-4c^2\right]=3\left(a-b-2c\right)\left(a-b+2c\right)\)
\(d,x^2-25+y^2+2xy=\left(x-y\right)^2-25=\left(x-y-5\right)\left(x-y+5\right)\)
Bài 1:
\(e,a^2+2ab+b^2-ac-bc=\left(a+b\right)^2-c\left(a+b\right)=\left(a+b-c\right)\left(a+b\right)\)
\(f,x^2-2x-4y^2-4y=\left(x-1\right)^2-\left(2y+1\right)^2=\left(x-2y-2\right)\left(x+2y\right)\)
\(g,x^2y-x^3-9y+9x=x^2\left(y-x\right)-9\left(y-x\right)=\left(x-3\right)\left(x+3\right)\left(y-x\right)\)
\(h,x^2\left(x-1\right)+16\left(1-x\right)=\left(x-1\right)\left(x-4\right)\left(x+4\right)\)
Bài 2:
1) \(4x^2-25+\left(2x+7\right)\left(5-2x\right)=\left(2x-5\right)\left(2x+5\right)-\left(2x+7\right)\left(2x-5\right)=\left(2x-5\right)\left(-2\right)\)
2) \(3\left(x+4\right)-x^2-4x=3\left(x+4\right)-x\left(x+4\right)=\left(3-x\right)\left(x+4\right)\)
3) \(5x^2-5y^2-10x+10y=5\left(x-y\right)\left(x+y\right)-10\left(x-y\right)=5\left(x-y\right)\left(x+y-2\right)\)
4) \(x^2-xy+x-y=\left(x-y\right)\left(x+1\right)\)
Bài 2:
5) \(ax-bx-a^2+2ab-b^2=x\left(a-b\right)-\left(a-b\right)^2=\left(a-b\right)\left(x-a+b\right)\)
6) \(x^2+4x-y^2+4=\left(x+2\right)^2-y^2=\left(x+y+2\right)\left(x-y+2\right)\)
7) \(x^3-x^2-x+1=x^2\left(x-1\right)-\left(x-1\right)=\left(x-1\right)^2\left(x+1\right)\)
Bài 2:
8) \(x^4+6x^2y+9y^2-1=\left(x^2+3y\right)-1=\left(x^2+3y+1\right)\left(x^2+3y-1\right)\)
9) \(x^3+x^2y-4x-4y=x^3\left(x+y\right)-4\left(x+y\right)=\left(x^3-4\right)\left(x+y\right)\)
10) \(x^3-3x^2+1-3x=x^2\left(x-3x\right)-\left(3x-1\right)=\left(x-1\right)\left(x+1\right)\left(3x-1\right)\)
Bài 2:
11) \(3x^2-6xy+3y^2-12z^2=3\left[\left(x-y\right)^2-4z^2\right]=3\left(x-y-2z\right)\left(x-y+2z\right)\)
12) \(x^2-2x-15=\left(x-1\right)^2-16=\left(x-5\right)\left(x+3\right)\)
13) \(2x^2+3x-5=\left(x-1\right)\left(2x+5\right)\)
Bài 2:
14) \(2x^2-18=2\left(x-3\right)\left(x+3\right)\)
15) \(x^2-7xy+10y^2=x^2-2xy-5xy+10y^2=x\left(x-2y\right)-5y\left(x-2y\right)=\left(x-2y\right)\left(x-5y\right)\)
mai em xin đến muộn lát nhé báo cơm chị nhé rảnh rỗi chị lại đi tiếp.