Assuming that the following variables have been declared,

String str1 = "Q.E.D.";

String str2 = "Arcturan Megadonkey";

String str3 = "Sirius Cybernetics Corporation";

Please evaluate the following expressions.

str3.substring(9, str3.indexOf("e"))
str3.substring(7, 12)
str2.toLowerCase().substring(9, 13) + str3.substring(18, str3.length() - 7)