1.2lg2+lg0.25=lg2^2+lg0.25=lg4+lg0.25=lg(4*0.25)=lg1=0
2.根据点到直线距离公式有d=|-5-7|/√(1^2+1^2)=6√2
3.f(x)=e^x
4.A∩B={6,8}
A∪B={1,6,8,10,12}
子集:空集、{1}、{6}、{8}、{10}、{12}、{1,6}、{1,8}、{1,10}、{1,12}、{6,8}、{6,10}、{6,12}、{8,10}、{8,12}、{10,12}、{1,6,8}、{1,6,10}、{1,6,12}、{1,8,10}、{1,8,12}、{1,10,12}、{6,8,10}、{6,8,12}、{8,10,12}、{1,6,8,10}、{1,6,8,12}、{1,8,10,12}、{6,8,10,12}、{1,6,8,10,12}