Read:
Numerical Mathematical Analysis
by Scarborough, James B
Introductory Methods of Numerical Analysis
by S.S. SASTRY
https://www.siirt.edu.tr/dosya/personel/numerik-analiz-siirt-2019217142654486.pdf
Click on the playlist below to get all the methods explained there...
https://www.youtube.com/playlist?list=PLX3dtITc4-LHnLH7nSph4oGwKZ1QY7NTE
All are important for the syllabus under Maulana Kalam Azad University of Technology
OEC-IT-601A
BSM 401
BSM 301