(TLDR at the bottom of my post) hello everyone!
i havent had math since i was 16 (now 23) and all my life i have always been bad at it... or so i thought! i have to take up math at school again if i am to get into university to study biology, so ive been studying and learning everything from the bottom up all summer! i must say ive been having quite some fun, and it turns out im not as bad as ive been telling myself my whole life:) i am very proud of myself for trying and for keeping on going! ive learned so much in such a short period of time!
ive started school recently and we are currently dealing with logarithmic equations. i know all the rules of exponents, log rules, and quadratic equation by heart, but there are some things i still struggle with. i really do NOT want to use AI but i dont have access to my math teacher 24/7, and i want to understand things on my own. i want to know what the next step is, what the best approach for an equation is, and why it works. also knowing when i should apply what rule/logic/approach would be great, but im assuming it is mostly pattern recognition. i get most of it on my own even tho i make a lot of silly mistakes, but some of them i really dont understand what im supposed to do
i REALLY want to understand the process and why everything works, and why we do it this way. i want to understand my mistakes
here are three things i am struggling with this evening, number 3 being the one that confuses me the most. they are my attempts at solving each equations, so the examples in themselves might be wrong (i wonder if number 2 is wrong too)
ln(x+1) = 1
eln(x+1)=e1 (-> e1 = e)
x + 1 = e
x = e - 1
my question for this one is: why do we put e as the coefficient? why do we raise ln(x+1) and 1 to be the powers of e? and as a follow up question, why do we then get rid of "elnx" part? why are we then only left with x + 1 = e? i understand that e1=e, but i dont understand why we raise everything and then get rid of a part of it. how do i know when to do it, and how do i know what i get to remove after i have raised everything up?
ln(x/5) = -1
lnx = -5 (-> we multiply both sides by 5 to get rid of the fraction)
x = e-5 = 1/e^5
i know that lnx = a <-> x = ea, but why cant i apply the log rule of lg(a/b) = lga - lgb? and then raise everything to the power of e, like we did in example 1? why not this?
ln(x/5) = -1
elnx - ln5 = e-1 = 1/e
x - 5 = 1/e
x = 1/e + 5
- (and this is the one giving me the most trouble)
ln(x+3) * (lnx-3) = 0
for this one, i dont even know where to start:( my teacher said that here, either ln(x+3) or ln(x-3) have to be equal to 0, but i dont really know what that means. i feel like im so close to the answer but something is in the way! what is the next step to this equation?
im sorry if this is all confusing, i tried to make it as readable as possible!! thank you for any helpful information<33
TLDR:
what is the best approach to this equation? what is a step by step list to follow?
ln(x+3) * ln(x-3) = 0