\(25-x^2-10xy-25y^2\)
\(=25-x^2-10xy-25y^2\)
\(=25-\left(x^2+10xy+25y^2\right)\)
\(=25-\left(x+5y\right)^2\)
\(=5^2-\left(x+5y\right)^2\)
\(=\left(5-x-5y\right)\left(5+x+5y\right)\)
Sửa đề: 25-x^2-10xy-25y^2
=25-(x^2+10xy+25y^2)
=25-(x+5y)^2
=(5-x-5y)(5-x+5y)