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# Log Equations?

0
405
3

5log(5)*(2v+4)-4=-9

Dec 10, 2014

#1
+10

If the problem is:  5log5(2v + 4) - 4  =  -9

Add 4 to both sides:     5log5(2v + 4)  =  -5

Divide both sides by 5:  log5(2v + 4)  =  -1

Write into exponential notation:  2v + 4  =  5-1    --->    2v + 4  =  1/5

Subtract 4 from both sides:        2v  =  -3.8

Divide both sides by 2:                v  =  -1.9

Dec 11, 2014

#1
+10

If the problem is:  5log5(2v + 4) - 4  =  -9

Add 4 to both sides:     5log5(2v + 4)  =  -5

Divide both sides by 5:  log5(2v + 4)  =  -1

Write into exponential notation:  2v + 4  =  5-1    --->    2v + 4  =  1/5

Subtract 4 from both sides:        2v  =  -3.8

Divide both sides by 2:                v  =  -1.9

geno3141 Dec 11, 2014
#2
0

Is that (5) base??

geno3141

I think it's log with base 10

and rest of them are just multiplying

Dec 11, 2014
#3
+8

I think that it is base 10 too

5log(5)*(2v+4)-4=-9

5log(5)*(2v+4)=-5

log(5)*(2v+4)=-1

(2v+4)=-1/log(5)

2v=-1/log(5)-4

v=[-1/log(5)-4]/2

$${\frac{\left({\mathtt{\,-\,}}{\frac{{\mathtt{1}}}{{log}_{10}\left({\mathtt{5}}\right)}}{\mathtt{\,-\,}}{\mathtt{4}}\right)}{{\mathtt{2}}}} = -{\mathtt{2.715\: \!338\: \!279\: \!036\: \!696\: \!4}}$$

Actually looking at the numbers Gino's interpretation is probably correct.