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Mathematics 13 Online
snowflake0531:

@darkknight dun dun dun~

snowflake0531:

sorry forgot practically all the properties of log .-.

snowflake0531:

Btw I got the first one tho lol

surjithayer:

2)128


2|64
2|32
2|16 ______ 2|8
2|4
|2 \[2^{x-5}=2^7\] x-5=7 x=7+5=12

snowflake0531:

thank you, although I got the first xd .-.

darkknight:

2nd one: \[3^{x+2}=27^{x-3}\] \[3^{x+2}=3^{3(x-3)}\] because 3^3 = 27 x+2 = 3(x-3) solve for x

snowflake0531:

x+2=3x-9 x=5.5

darkknight:

to check if you did it right you can put the value of x back into the equation

snowflake0531:

both 3798 then blah blah blah xd

snowflake0531:

*3787

darkknight:

for the 3rd one (top to bottom not left to right) you can move the -log base 2 10 to the other side, then exponentiate both sides by 2 to get rid of the log base 2

darkknight:

You will be left with \[2x^2+4x-2=10\] then solve for x

darkknight:

dont forget to plug in value for x back in to double check

snowflake0531:

can't factor it <.<

darkknight:

quadratic formula, bring everything to 1 side

snowflake0531:

._. okok one sec

surjithayer:

7. \[(\frac{ 1 }{ 243 })^x=27\] 3|243


3|81 _____ 3|27 _____ 3|9 _____ |3 \[(\frac{ 1 }{ 3^5 })^x=3^3\] \[(3^{-5})^x=3^3\] \[3^{-5x}=3^3\] -5x=3 \[x=\frac{ -3 }{ 5 }=-0.6\]

snowflake0531:

\[\frac{ -4 \pm \sqrt(16+96) }{ 4 } \\ \frac{ -4 \pm \sqrt(112 }{ 4 } \\ \frac{ -4 \pm 4\sqrt(7) }{ 4 } \\ -1 \pm \sqrt(7) \]

snowflake0531:

@surjithayer wrote:
7. \[(\frac{ 1 }{ 243 })^x=27\] 3|243 3|81 _____ 3|27 _____ 3|9 _____ |3 \[(\frac{ 1 }{ 3^5 })^x=3^3\] \[(3^{-5})^x=3^3\] \[3^{-5x}=3^3\] -5x=3 \[x=\frac{ -3 }{ 5 }=-0.6\]
okay thxxxxxxx

surjithayer:

log(2x+4)-log(3x)=0 \[\log \frac{ 2x+4 }{ 3x }=0\] \[\frac{ 2x+4 }{ 3x }=1\] 2x+4=3x 3x-2x=4 x=4

snowflake0531:

okok got that thx xd

surjithayer:

\[2x^2+4x-2=10\]\[2x^2+4x-12=0\] \[x^2+2x-6=0\] \[x^2+2x+1=6+1\] \[x+1=\pm \sqrt{7}\] \[x=-1 \pm \sqrt{7}\]

Florisalreadytaken:

i had to get my hands on this haha! \[ \frac{ \log _{3}(3 x+6)}{\log _{3} 81}=1 \] \[ \overset{\text{get rid of the denominator}}{==========\Rightarrow} \log _3\left(3x+6\right)=\log _3\left(81\right) \Rightarrow \cancel{\log _3}\left(3x+6\right)=\cancel{\log _3}\left(81\right) \] \[ 3x+6=81 \] you solve the rest

surjithayer:

11. \[\frac{ \ln (x+7) }{ \ln (2x-3) }=1\] \[\ln (x+7)=\ln (2x-3)\] or x+7=2x-3 x=?

snowflake0531:

@florisalreadytaken x=25 @surjithayer x=10 that was a lot to read through .-. xddd thanks you guys lmao

snowflake0531:

and then the last one for #12 13/4?

Florisalreadytaken:

we left one i think: 12) \[ \frac{\log (4 x+2)}{\log (15)}=1 \] \[ \overset{ \text{same for tihis one, get rid of the denominator}}{==================\Rightarrow} \log _{10}\left(4x+2\right)=\log _{10}\left(15\right) \Rightarrow \\ \cancel{\log _{10}}\left(4x+2\right)=\cancel{\log _{10}}\left(15\right) \] \[ 4x+2=15 \] \[ 4x=15-2 \] \[ x=\frac{13}{4} \] \[ x=?? \]

snowflake0531:

3.25 xd thx

Florisalreadytaken:

yeah whatever that is -- is there any left one?

snowflake0531:

nope lol thanks surjithayer, flor, and dark xddddd <3

surjithayer:

yw

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