Log(base 3) (x^2-9) - Log(base 3) (x+1) = 2
show work please!
wow I did this like 2 weeks ago and got a 99 on the exam, and I totally forgot how to do these hahah thats sweet.
log(base3) ((x^2-9) / (x+1) = 2
((x^2-9) / (x+1) = 3^2
x^2-9 = 9(x + 1)
x^2-9 - 9x - 9 = 0
x^2 - 9x - 18 = 0
x = (9 +- sqrt(81 + 72)) / 2
= (9 +- sqrt(153)) / 2
although the negative answer is no good because we end up with a negative numberin the log and you can't take the log of a negative so the answer is
x = (9 + sqrt(153)) / 2
= 10.68 (2dp)
log(base3)(x^2-9) (divided by) log(base3)(x+1)=2
log(base3) (x^2-9)/(x+1) =2
3^2 = (x^2-9)/(x+1)
9 = (x^2-9)/(x+1)
9(x+1) = (x^2-9)
9x+9 = x^2-9
x^2-9-9x-9 = 0
x^2-9x-18 = 0
then use the quadratic formula from there b/c the roots aren't whole integers
HOPE THIS HELPS N GIVES U COMPREHENSION ^_^
(x^2-9)/(x+1)=9
x^2-9x-18=0
x=10.7
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wow I did this like 2 weeks ago and got a 99 on the exam, and I totally forgot how to do these hahah thats sweet.
Log(base 3) (x^2-9) - Log(base 3) (x+1) = 2
log(base3) ((x^2-9) / (x+1) = 2
((x^2-9) / (x+1) = 3^2
x^2-9 = 9(x + 1)
x^2-9 - 9x - 9 = 0
x^2 - 9x - 18 = 0
x = (9 +- sqrt(81 + 72)) / 2
= (9 +- sqrt(153)) / 2
although the negative answer is no good because we end up with a negative numberin the log and you can't take the log of a negative so the answer is
x = (9 + sqrt(153)) / 2
= 10.68 (2dp)
Log(base 3) (x^2-9) - Log(base 3) (x+1) = 2
log(base3)(x^2-9) (divided by) log(base3)(x+1)=2
log(base3) (x^2-9)/(x+1) =2
3^2 = (x^2-9)/(x+1)
9 = (x^2-9)/(x+1)
9(x+1) = (x^2-9)
9x+9 = x^2-9
x^2-9-9x-9 = 0
x^2-9x-18 = 0
then use the quadratic formula from there b/c the roots aren't whole integers
HOPE THIS HELPS N GIVES U COMPREHENSION ^_^
(x^2-9)/(x+1)=9
x^2-9x-18=0
x=10.7