All ACT Math Resources
Example Questions
Example Question #111 : Exponents
If , then ?
15
4
5
25
10
5
Calculate the power of that makes the expression equal to 25. We can set up an alternate or equivalent equation to solve this problem:
Solve this equation by taking the square root of both sides.
, because logarithmic equations cannot have a negative base.
The solution to this expression is:
Example Question #1 : How To Find A Ratio Of Exponents
If and , then which of the following CANNOT be the value of ?
Even roots of numbers can either be positive or negative. Thus, x = +/- 5 and y = +/- 3. The possible values from x + y can therefore be:
(-5) + (-3) = -8
(-5) + 3 = -2
5 + (-3) = 2
5 + 3 = 8
Example Question #2 : How To Find A Ratio Of Exponents
If for all not equal to 0, which of the following must be true?
Remember that
Since the problem states that , you can assume that
This shows that .
Example Question #1 : How To Find A Ratio Of Exponents
If and are positive integers and , then what is the value of ?
43 = 64
Alternatively written, this is 4(4)(4) = 64 or 43 = 641.
Thus, m = 3 and n = 1.
m/n = 3/1 = 3.
Example Question #2 : How To Find A Ratio Of Exponents
Write the following logarithm in expanded form:
Example Question #2 : How To Find A Ratio Of Exponents
If and are both rational numbers and , what is ?
This question is asking you for the ratio of m to n. To figure it out, the easiest way is to figure out when 4 to an exponent equals 8 to an exponent. The easiest way to do that is to list the first few results of 4 to an exponent and 8 to an exponent and check to see if any match up, before resorting to more drastic means of finding a formula.
And, would you look at that. . Therefore, .
Example Question #1 : How To Find The Square Of Difference
can be rewritten as:
Use the formula for solving the square of a difference, . In this case,
Example Question #1 : Squaring / Square Roots / Radicals
Expand:
To multiply a difference squared, square the first term and add two times the multiplication of the two terms. Then add the second term squared.
Example Question #2 : Squaring / Square Roots / Radicals
The expression is equivalent to:
First, we need to factor the numerator and denominator separately and cancel out similar terms. We will start with the numerator because it can be factored easily as the difference of two squares.
Now factor the quadratic in the denominator.
Substitute these factorizations back into the original expression.
The terms cancel out, leaving us with the following answer:
Example Question #1 : Squaring / Square Roots / Radicals
Evaluate the following expression:
2 raised to the power of 5 is the same as multiplying 2 by itself 5 times so:
25 = 2x2x2x2x2 = 32
Then, 5x2 must first be multiplied before taking the exponent, yielding 102 = 100.
100 + 32 = 132