Question

How do I solve this?

Answer 1

x=2

logx+log(x+3)=1

logx(x+3)=log10

x²+3x=10

x²+3x-10=0

a=1 b=3 c=-10

D=b²-4ac=3²-4×1×(-10)=9+40=49

x1= -3+7 /2= 2

x2= -3-7 /2= -5 (this solution is invalid because x is supposed to be x>0)

This are the rules you need to know:

$log_{x}(ab) = log_{x}(a) + log_{x}(b)$

and

$log_{2}(2) = 1$