SOLUTION: Use algebraic procedures to find the exact solution of the equation log4x+log4(x-12)=3. a. 16 b. -4,16 c. 0,-12 d. 4 e. 3,4

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: Use algebraic procedures to find the exact solution of the equation log4x+log4(x-12)=3. a. 16 b. -4,16 c. 0,-12 d. 4 e. 3,4      Log On


   

Question 470555: Use algebraic procedures to find the exact solution of the equation
log4x+log4(x-12)=3.
a. 16
b. -4,16
c. 0,-12
d. 4
e. 3,4
Found 2 solutions by robertb, lwsshak3:
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
a. 16.
Just quickly try out all the possible choices, and you'll find out it's 16.

Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
Use algebraic procedures to find the exact solution of the equation
log4x+log4(x-12)=3.
**
log4x+log4(x-12)=3
=log4(x(x-12))=3
convert to exponential form (base(4) raised to log of number(3)=number(x(x-12))
4^3=x(x-12)
64=x^2-12x
x^2-12x-64=0
(x-16)(x+4)=0
x=16
or
x=-4 (reject, 4x>0)
..
Check:
log4(16)+log4(16-12)
=log4(16)+log4(4)
=2+1=3