点到直线距离d=|ax0+by0+c|/√(a²+b²)
=|-2(1+3a)-(1+2a)-(2+5a)|/√((1+3a)^2+(1+2a)^2)
=|2+6a+1+2a+2+5a|/√(1+6a+9a^2+1+4a+4a^2)
=|2+6a+1+2a+2+5a|/√(1+6a+9a^2+1+4a+4a^2)
=|5+13a|/√(2+10a+13a^2)
=13|5/13+a|/√13(2/13+10a/13+a^2)
=√13|a+5/13|/√(a^2+10a/13+2/13)
=0
所以0