Answer
$-21$
Work Step by Step
$(g\circ f)(0)=g(f(0))=g(2\cdot0-5)=g(-5)=5\cdot(-5)-1=-21$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.