Solve: log (x +4)+ log (x…

Discussion in 'Mathematics' started by Stylewise, Dec 31, 2015.

  1. Stylewise

    Stylewise New Member

    Joined:
    Aug 4, 2015
    Messages:
    0
    Likes Received:
    0
    Solve: log (x +4)+ log (x +1)=1
     
  2. MofShido

    MofShido New Member

    Joined:
    Jan 15, 2013
    Messages:
    0
    Likes Received:
    0
    Since bases of logarithms are same, we can multiply (x +4) by (x +1); log (x +4)+ log (x +1) ⇒ log (x +4) (x +1) ⇒ log (x²+5 x +4)=1Now convert it to exponent formassume base is 10) x²+5 x +4=10^1 x²+5 x +4=10 x²+5 x — 6=0Now we can factor it; x²+5 x — 6=0 ⇒ (x +6) (x — 1)=0So answer so far is x=-6 or 1. Plug them into initial equation and progress; You will see that -6 isn't possibleSo we are left with x=1
     

Share This Page