Bài 1:
a,x^{2}+5x+5xy+25y=x(x+5y)+5(x+5y)=(x+5)(x+5y)
b,x^{2}-y^{2}+14x+49=(x+7)^{2}-y^{2}=(x+7-y)(x+7+y)
c,x^{2}-24x-25=x(x-25)+(x-25)=(x+1)(x-25)
d,4x-8y=(2\sqrt{x}-\sqrt{8y})(2\sqrt{x}+\sqrt{8y})
e,x^{2}+2xy+y^{2}-16=(x+y)^{2}-16=(x+y-4)(x+y+4)...