2x=32
Solve for x
2x=32
1. Rewrite with common base 2x=25
2. The bases cancel out x=5
ex+5=60
Solve for x
1. Take 5 from each side ex=55
2. Take natural log of each side ln ex=ln 55
3. Impliment the Inverse Property x=ln 55/x=4.007
e2x-4ex-5=0
Solve for x
1. Rewrite the equation (ex)2-4ex-5
2. Factor (ex-5)(ex+1)
3. Rewrite ex-5=0
4. Multiply by ln and solve for x
x=ln5
x=1.609
lnx= -3
Approximate the result to 3 decimal places
1. Do the circle thingy
3-3=x
2. Solve
e-3 = -0.223
What is the One-To-One Property and how is it used to solve a logarithmic equation?
ax=ay
The One-To-One Property is if Y=X then it is One-To-One
You apply the Property to a logarithmic equation by if the base of a logarithm on either side is the same then they cancel out.
5-ex=0
Solve for x
1. Move e on other side 5=ex
2. Use natural log to cancel out base of e ln 5=ln ex
3. The ln cancels out e. Rewrite ln 5=x
2(5x)=32
Solve for x
1. Divide each side by 2 5x=16
2. Take log5 to isolate x log55x=log516
3 . Rewrite
x=log516
4. Solve using the change of base property log 16 over log 5 (log16)/(log5)
5. Solve for x x=1.722
e2x-5ex+6=0
Solve for x
1. Rewrite using substitution
(ex)2-5ex+6=0
2. Factor
(ex-3)(ex-2)=0
3. Rewrite
ex-3=0
4. Take ln of each side and solve for x
x=ln3
x=1.098
log4x-log4(x-1)=1/2
Approximate the result to three decimal places, if necessary
1. Rewrite the equation using the Quotient Property
log4(x/x-1)=1/2
2. Rewrite
(x/x-1)=41/2
3. Write in exponential form
(x/x-1)=(22)1/2
4. Simplify
(x/x-1)=2
5. Multiply by x-1
x=2(x-1)
6. Distribute
x=2x-2
7. Solve for x
x=2
What are the strategies for solving exponential and logarithmic equations?
1. Rewrite fthe origional equation in a form that allows the use of the One-To-One Properties of exponential or logarithmic functions.
2. Rewrite an exponential equation in logarithmic form and apply the Inverse Property of logarithmic functions.
3. Rewrite a logarithmic equation in exponential form and apply the Inverse Property of exponential functions.
log6x=3
Solve for x
1. Use the Circle method thingy and rewrite as an exponential equation 63=x
2. Solve x=216
ex-7=23
Solve for x
1. Subtract 7 from each side ex=30
2. Take natural log of each side lnex=ln30
3. Rewrite to isolate x x=ln30
4. Solve x=3.401
e2x-7ex-12=0
Solve for x
1. Rewrite using substitution
(ex)2-7ex-12=0
2. Factor
(ex-3)(ex-9)
3. Rewrite
ex-3=0
4. Take ln of each side
x=ln3
x=1.098
log2(x+2)+log2(3)=log2(27)
Solve for x
1. Reduce log2(27)
log2(x+2)+log2(3)=log2(33)
2. Drop exponent
log2(x+2)+log2(3)=3log2(3)
3. Move constant to the right side of the equation.
log2(x+2)=3log2(3)-log2(3)
4. Combine like terms
log2(x+2)=2log2(3)
5. Use the Power Property and lift exponent
log2(x+2)=log2(32)
6. Bases cancel out
x+2=32
7. Solve for x
x=7
What the Inverse Property
The Inverse Property states that a number added to it's opposite will equal zero.
What is the Quotient Rule?
The log of a quotient is equal to the difference of the logs of the numerator and denominator.
What is the Product Rule?
The log of a product is equal to the sum of the log of the first base and the log of the second base.