Hi there! My name is Zalgo and I am here to help you out on this wonderful day. "23+x=3", it seems that we need to find the "X value". That would be "-20". In order to test that it is the correct answer, just input it into the equation. "23+-20=3".
I hope that this helps! :)
"Stay Brainly and stay proud!" - Zalgo
(By the way, do you mind marking me as Brainliest? I'd greatly appreciate it! Thank you! XP)