Download Math 125 Section 4.4 – logarithmic and exponential equations

Math 125 Section 4.4 – logarithmic and exponential equations
Approach:
1) Simplify fully
2) Determine if equation is logarithmic or exponential
3) Look for proper form and solve
4) Check answer
If Logarithmic
FORMS:
1) log a (u)=log a (v)
solution is
u=v
example: log(x) = log(x+3) – log(x-1)
2)
log a (u)=v
solution is to use the definition of logarithm
v
a =u
log 5 (2x−3)=2
example:
** always check as you can never take the log of a negative number
If Exponential
FORMS:
1) au =a v
solution is
u=v
example:
x
9 =27
2)
u
a =v
solution comes after taking the ln() of both sides and solving
example:
x
3 =5
DO p. 250 (2, 5, 8, 14, 18, 24, 32, 65)
3( 2x−1)=4( x +2)