a) ( x-3y ) ( x + 1 )
b) ( x+y+5 ) ( x+y-5 )
c) ( x-5 ) ( x+2 )
Hk tốt
a) \(x^2-3xy+x-3y=x\left(x-3y\right)+\left(x-3y\right)=\left(x+1\right)\left(x-3y\right)\)
b) \(x^2-25+9y^2-6xy=\left(x-3y\right)^2-25=\left(x-3y-5\right)\left(x-3y+5\right)\)
c) \(x^2-3x-10=x^2+2x-5x-10=x\left(x+2\right)-5\left(x+2\right)=\left(x-5\right)\left(x+2\right)\)