All ACT Math Resources
Example Questions
Example Question #3 : Logarithms
Evaluate
log327
10
9
30
3
27
3
You can change the form to
3x = 27
x = 3
Example Question #1 : Logarithms
If , what is ?
If , then
Example Question #1 : Logarithms
If log4 x = 2, what is the square root of x?
16
4
2
3
12
4
Given log4x = 2, we can determine that 4 to the second power is x; therefore the square root of x is 4.
Example Question #2 : Logarithms
Solve for x in the following equation:
log224 - log23 = logx27
–2
1
9
3
2
3
Since the two logarithmic expressions on the left side of the equation have the same base, you can use the quotient rule to re-express them as the following:
log224 – log23 = log2(24/3) = log28 = 3
Therefore we have the following equivalent expressions, from which it can be deduced that x = 3.
logx27 = 3
x3 = 27
Example Question #2 : Logarithms
What value of satisfies the equation ?
The answer is .
can by rewritten as .
In this form the question becomes a simple exponent problem. The answer is because .
Example Question #4 : Logarithms
If , what is ?
Use the following equation to easily manipulate all similar logs:
changes to .
Therefore, changes to .
2 raised to the power of 6 yields 64, so must equal 6. If finding the 6 was difficult from the formula, simply keep multiplying 2 by itself until you reach 64.
Example Question #5 : Logarithms
Which of the following is a value of that satisfies ?
The general equation of a logarithm is , and
In this case, , and thus (or , but is not an answer choice)
Example Question #791 : Algebra
How can we simplify this expression below into a single logarithm?
Cannot be simplified into a single logarithm
Using the property that , we can simplify the expression to .
Given that and
We can further simplify this equation to
Example Question #101 : Exponents
What is the value of ? Round to the nearest hundredth.
You could solve this by using your calculator. Remember that you will have to translate this into:
Another way you can solve it is by noticing that
This means you can rewrite your logarithm:
Applying logarithm rules, you can factor out the power:
For any value , . Therefore, . So, your answer is .
Example Question #2291 : Act Math
Solve for
.
Round to the nearest hundredth.
To solve an exponential equation like this, you need to use logarithms. This can be translated into:
Now, remember that your calculator needs to have this translated. The logarithm is equal to the following:
, which equals approximately .
Remember that you have the equation:
Thus, .