#logarithms y12
139 messages · Page 1 of 1 (latest)
So 3 × 2^x = 15 - 2^(x+1)
All u have to notice is that 2^(x+1) = 2 × 2^x
Yes
No need to re-write that
i don't get the second line
what do i do w the 15 and the 3
Its just laws of indicies
Ok to make it easier to visualise let u=2^x
ignore the pencil but this is what i've got
if this comes up on my mock i will kms 😭
The log step is the last step
I think i just overcomplicated it
Let u = 2^x
So we're just solving 3u = 15-2u
?
6^x = (3×2)^x not 3 × (2^x)
is that not just 6^x
Nope
how is that not 6^x
^
I think ur overcomplicating it
Look
3×2^x = 15 - 2^(x+1)
3×2^x = 15 - 2×2^x
Instead of writing 2^x write u
3u=15-2u
5u=15
u=3
2^x = 3
x = log base 2 of 3
where the hell did the other 2 come from
the 2nd line
the second line of ur workings
where did the other 2 come from 😭
2^(x+1) = 2×2^x
Raising something to the power of something is just repeated multiplication right?
So 3^4 is just 3×3×3×3
this line baffles me:
i'm still genuinely so confused where the extra 2 from the rhs came from
girl i was meant to start modelling with logs half an hour ago but i'm stuck on this
Ok
2¹ × 2^x by laws of indicies the powers add so it equals 2^(x+1)
Does that make sense
Like 2⁵ = 2 × 2⁴
2¹⁰⁰ = 2 × 2⁹⁹
yep
Oh ok u got it
but here the terms are different
it's 3 and 2
they're not the same so idk what to do
The 3 and the 2 are like coefficients
kinda like how u can't do a^2 x b^3
i mean
u can to get a^2b^3
but not like (ab)^5
Multiplication is just repeated addition so if it makes it easier
3×2^x = 2^x + 2^x + 2^x
yeah so 2^x times that by 2^x times that by 2^x
wait
why are we
nvm
i'll go w the adding
so that should surely be 6^x???
Adding not multiplying
this is so fucking confusing bro i'm literally crying
yeah that's still the same inni??
if i were to multiply instead that would just be 8x^3
Not x times x times x
Wait what?
where did the extra 2 come from
yeah
i'm just like
where did the extra 2 come from
2x2^x is just 4^x
I thought u said u understood that...
i understand the other bits after i just don't get that
The base stays the same
Like gcse laws of indicies
so 2^1 * 2^x
Yesss
that's just 2^x+1
Yessss
what am i gonna take from there?? 😭
Then u just rearrange to make 2^x the subject
What cancels out?
I swear if ur trolling
so we have to assign some sort of variable to it
i swear i'm not
i'm literally crying in a classroom over this question
Oh ok
That can make it easier
Like u=2^x
holy shit why is the quality so bad
Oh damn
i was meant to learn exponentials almost an hour ago but i'm stuck on this
like wtf happens to it
i'm just gonna pray this question doesn't come up on the mock
?
$a * b^x + c * b^x = (a+c)b^x$
riad
The star is multiplication
clarence cant solve d1s
$a×b$
arizus
🧠🧠