Help solve log

Question

-3*10^m+1 - 7 = -25

 

Answer 1

-3(10)^{m + 1} - 7 = -25

 

 

Add 7 on both sides of equation .

 

-3(10)^{m + 1} = -18

 

 

Divide both sides of equation by -3.

 

10^{(m + 1)} = 6

 

 

Log both sides of equation.  Bring down the exponent as the coefficient of the log.

 

(m + 1)log10 = log(6)

 

 

Divide both sides of equation by log10.

 

m + 1 = (log6) / (log10)

 

m + 1 = 0.778

 

 

Subtract 1 on both sides of equation.

 

m = -0.222

Answer 2

-3*10^(m+1)-7=-25

-3*10^(m+1)=-25+7

-3*10^(m+1)=-18

10^(m+1)=6

log10^(m+1)=log6 (both logs are base 10)

(m+1)log10=log6

m+1=log6

m+1=0.77815125

m=-1+0.77815125

m=-0.22184875

check: 10^(0.77815125)=5.9999999947