(lg5)^2+lg2*lg50+6lg√10=(lg5)^2+lg2*lg2*25+6lg10^(1/2)=(lg5)^2+lg2(lg2+lg25)+6/2lg10=(lg5)^2+(lg2)^2+lg2*lg5^2+3=(lg5)^2+2lg2lg5+(lg2)^2+3=(lg5+lg2)^2+3=(lg10)^2+3=1+3=4