2lg5*lg2=

(lg5)^2+lg5.lg2= (lg2)^2+lg2*lg5+(lg5)^2= 2lg5*lg2= =(lg5)^2+lg2×lg5+lg2 =lg5×(lg5+lg2)+lg2麻烦问一下,这是咋做的 lg2^2+lg2*lg5+lg5=lg2(lg2+lg5)+lg5这个过程中,lg2的平方怎么没了? lg5*lg2=lg5+2吗?为什么? lg50+lg2*lg5+(lg2)^2= lg^2 5+lg2*lg5+lg2=? lg5*(1+lg2)+(lg2)^2= lg5+2lg2+（lg2）=? lg5+2lg2-lg2=什么 lg2*lg2+lg5-lg2=? (lg2)^2+(lg5)^2=? (lg5)^2+lg2×lg50=? (lg5)^2 + (lg2)*(lg50)= (lg5)^2+lg2*lg50= 2lg2+lg7+lg5= (lg2)^3+(lg5)^2=