a) \(x^2-2x-15\)

\(\Leftrightarrow x^2-2x+1-16\)

\(\Leftrightarrow\left(x-1\right)^2-4^2\)

\(\Leftrightarrow\left(x-5\right)\left(x-3\right)\)

\(a,x^2-2x-15=\left(x^2-2x+1\right)-16.\)

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

\(=\left(x-5\right)\left(x+3\right)\)

b)\(5x^2y^3-25x^3y^4+10x^3y^3\) 

 \(=5x^2y^3\left(1-5xy+2x\right)\) 

c)\(12x^2y-18xy^2-30y^2\) 

 \(=6y\left(2x^2-3xy-5y\right)\)

đề dài nên T giải câu a thôi bn tự làm tiếp mấy câu khác nhé 

2x^2 - 2y^2 - 6x - 6y 

= 2(x^2-y^2) - 6(x+ y) 

= 2(x-y)(x+y) - 6(x+y) 

= (2(x-y)-6) (x+y)

ko biết

\(12x^2y-18xy^2-30y^2=6y\left(2x^2-3xy-5y\right)\)

\(d,5\left(x-y\right)-y\left(x-y\right)=\left(5-y\right)\left(x-y\right)\)

d)5.(x-y)-y(x-y)

=(x-y)(5-y)

e) y.(x-z)+7(z-x)

=y.(x-z)-7(x-z)

=(x-z)(y-7)

1, \(3x^2y^2-6x^2y^3+9x^2y^2\)

\(\Leftrightarrow12x^2y^2-6x^2y^2\)

\(\Leftrightarrow3x^2y^2\left(4+2y\right)\)

5x^2y^3 - 25x^3y^4 + 10x^3y^3

\(\Leftrightarrow5x^2y^3\left(1-5xy+2x\right)\)

\(12x^2y-18xy^2+30y^2\)

\(\Leftrightarrow6y\left(2x^2-3xy-5y\right)\)

mình cũng bạch dương nè

\(x^3-2x^2+x=x^3-x^2-x^2+x\)

\(=\left(x^3-x^2\right)-\left(x^2-x\right)\)

\(=x^2\left(x-1\right)-x\left(x-1\right)\)

\(=\left(x^2-x\right)\left(x-1\right)\)

\(e,36-12x+x^2=6^2-2.6x+x^2\)

\(=\left(6-x\right)^2\)

\(g,11x+11y-x^2-xy=\left(11x+11y\right)-\left(x^2+xy\right)\)

\(=11\left(x+y\right)-x\left(x+y\right)\)

\(=\left(11-x\right)\left(x+y\right)\)

rút gọn= 10x²y²-250x⁶y⁷=10x²y²(1-25x⁴y⁵)

thế nhá

Bài 3: 

a: \(x^2-16=\left(x-4\right)\cdot\left(x+4\right)\)

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

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