Post your code (rather than a picture of your code) so we don't have to type it out. See Wiki - how to post code on this forum.
system.tag.writeBlocking's syntax is
system.tag.writeBlocking([list-of-tag-paths], [list-of-values])
It runs through the list of tag paths and does a write to each of those using the corresponding value from the list of values. You need to get that value using system.tag.readBlocking([list-of-tag-paths]) first.