How do you find the absolute value: |5-i|? Precalculus Complex Numbers in Trigonometric Form Complex Number Plane 1 Answer Shwetank Mauria Jun 29, 2016 #|5-i|=sqrt26# Explanation: Absolute value #|a+ib|=sqrt(a^2+b^2)# Hence #|5-i|# = #sqrt(5^2+(-1)^2)# = #sqrt(25+1)# = #sqrt26# Answer link Related questions What is the complex number plane? Which vectors define the complex number plane? What is the modulus of a complex number? How do I graph the complex number #3+4i# in the complex plane? How do I graph the complex number #2-3i# in the complex plane? How do I graph the complex number #-4+2i# in the complex plane? How do I graph the number 3 in the complex number plane? How do I graph the number #4i# in the complex number plane? How do I use graphing in the complex plane to add #2+4i# and #5+3i#? How do I use graphing in the complex plane to subtract #3+4i# from #-2+2i#? See all questions in Complex Number Plane Impact of this question 3738 views around the world You can reuse this answer Creative Commons License