IB algebra

hi y'all
i'm revising for a test on ib (sl) algebra and i'm, like, moments from ripping all of my hair out
also i missed quite a bit of lessons on this so this question might be real stupid but bear with me

q1: solve for t: 4^(t)=1/1024
i went with multiplying both sides by 1024, then (t)log4096=1 and t=1/log4096. i got 0.277, the answer is apparently -5.
q2: solve for x: 2^(2x)-2^(x+1)+8 = 0
i let 2^(x)=y and tried to solve it like a quadratic but it wouldn't factorize.
the answers are probably really obvious so sorry in advance for posting this!!

Reply 1

Egos

11

For Q1:
4^t can be written as 2^2t
1/1024 cab be written as 2^(-10)
Therefore you get 2t=-10
t=-5
For Q2:
XXXXXXX
Hope it helps :smile:

Just noticed my mistake sorry. So I am deleting the answer for q2.

Posted from TSR Mobile

(edited 11 years ago)

Reply 2

boner in jeans

Original post by Rorsy

hi y'all
i'm revising for a test on ib (sl) algebra and i'm, like, moments from ripping all of my hair out
also i missed quite a bit of lessons on this so this question might be real stupid but bear with me

q1: solve for t: 4^(t)=1/1024
i went with multiplying both sides by 1024, then (t)log4096=1 and t=1/log4096. i got 0.277, the answer is apparently -5.
q2: solve for x: 2^(2x)-2^(x+1)+8 = 0
i let 2^(x)=y and tried to solve it like a quadratic but it wouldn't factorize.
the answers are probably really obvious so sorry in advance for posting this!!

1) BEDMAS you can't multiply something with an exponent that isn't the same base i.e.

4^{t} = \frac{1}{1024} \neq 4096^{t} = 1

just take logs from the start

2) if it doesn't factorise, use the quadratic formula

(edited 11 years ago)

Reply 3

boner in jeans

Original post by Rorsy

hi y'all
i'm revising for a test on ib (sl) algebra and i'm, like, moments from ripping all of my hair out
also i missed quite a bit of lessons on this so this question might be real stupid but bear with me

q1: solve for t: 4^(t)=1/1024
i went with multiplying both sides by 1024, then (t)log4096=1 and t=1/log4096. i got 0.277, the answer is apparently -5.
q2: solve for x: 2^(2x)-2^(x+1)+8 = 0
i let 2^(x)=y and tried to solve it like a quadratic but it wouldn't factorize.
the answers are probably really obvious so sorry in advance for posting this!!

also OP are you sure you've posted q2 correctly?

i have good reason to believe the solution does not exist

Reply 4

ztibor

10

Original post by Rorsy

hi y'all
i'm revising for a test on ib (sl) algebra and i'm, like, moments from ripping all of my hair out
also i missed quite a bit of lessons on this so this question might be real stupid but bear with me

q1: solve for t: 4^(t)=1/1024
i went with multiplying both sides by 1024, then (t)log4096=1 and t=1/log4096. i got 0.277, the answer is apparently -5.
q2: solve for x: 2^(2x)-2^(x+1)+8 = 0
i let 2^(x)=y and tried to solve it like a quadratic but it wouldn't factorize.
the answers are probably really obvious so sorry in advance for posting this!!