I think this is the old artist of Why Would a Villainess Have Virtues?
https://www.mangago.zone/read-manga/why_would_a_villainess_have_virtue/
Watch khan academy or the organic chemistry tutor on YouTube they have pretty much all math equations explained on their channels. And just do like 10 questions of each problem your having trouble with. Only way to study math if your not naturally good at it (me rip)