help with a few questions please :)

[sisqo1111]

Hi all,
my teacher has set a few exercises for homework over the weekend but im having a fewproblems with some. Any help would be very grateful.
its on logs lol.
Ok off we go
Solve for
x: in the following:
1) 3-log_10x=log_102       - sorry i dnt know ho to do log to base 10 so thats what the underscore is     
2) (log_10x)^2+log_10x-2 = 0
3) log_10  (x^2+ 2 x -5)= 1         Thanks a heap

Sorry to be a pain but also there is one extended question and it says:
The decible(dB) scale for measuring loudness, d, is given by the formula d= 10log_10 (I X 10^12), where I is the intensity of sound in watts per square meter.
and a) asks, find the number of decibles of sound if the intensity is 1.
So i subbed 1 where I is and get some wierd 1e something

Any help would be awesome
VCE Notes Rocks!                                                                              

[Four]

1)
Therefore:


2) Let ...

a = -2 is rejected, therefore:


3)
Therefore:


x = -5 or x = 3

[sisqo1111]

thanks for that but with question 2,
the book says x= 10 and 1/100

[Mao]

for question 2:








or

[sisqo1111]

thanks mao! awesome help
any chance for help with the extended response at the end of my first post its quite small

[Toothpaste]

Sorry to be a pain but also there is one extended question and it says:
The decible(dB) scale for measuring loudness, d, is given by the formula d= 10log_10 (I X 10^12), where I is the intensity of sound in watts per square meter.
and a) asks, find the number of decibles of sound if the intensity is 1.
So i subbed 1 where I is and get some wierd 1e something

Any help would be awesome
VCE Notes Rocks!                                                                             

Yay? Nay?

[sisqo1111]

Yay
awesomeeee
thankyouu

[droodles]

even i could do that one

[sisqo1111]

allright good for you