All PSAT Math Resources
Example Questions
Example Question #982 : Psat Mathematics
If , find the value of .
f(4) = 4 + 1/4 = 16/4 + 1/4 = 17/4
Example Question #1025 : Algebra
If and , what is ?
100
104
19
132
20
132
g is a function of f, and f is a function of 3, so you must work inside out.
f(3) = 11
g(f(3)) = g(11) = 121 + 11 = 132
Example Question #1026 : Algebra
Jamie buys a new fish tank. It is 45% full. She adds seven more liters of water, and it is 65% full. What is the capacity of Jamie's new fish tank?
22 liters
27 liters
None of the other answers are correct.
35 liters
48 liters
35 liters
The algebraic expression for x, the capacity of the fishtank is:
The capacity of the fishtank is 35 liters.
Example Question #61 : How To Find F(X)
When we multiply a function by a constant, we multiply each value in the function by that constant. Thus, 2f(x) = 4x + 12. We then subtract g(x) from that function, making sure to distribute the negative sign throughout the function. Subtracting g(x) from 4x + 12 gives us 4x + 12 - (3x - 3) = 4x + 12 - 3x + 3 = x + 15. We then add 2 to x + 15, giving us our answer of x + 17.
Example Question #62 : How To Find F(X)
If , what is the smallest possible value of ?
8
4
12
6
10
6
This equation describes a parabola whose vertex is located at the point (4, 6). No matter how large or small the value of t gets, the smallest that f(t) can ever be is 6 because the parabola is concave up. To prove this to yourself you can plug in different values of t and see if you ever get anything smaller than 6.
Example Question #1031 : Algebra
If , then ?
To find when , we substitute for in .
Thus, .
We expand to .
We can combine like terms to get .
We add 3 to this result to get our final answer.
Example Question #1032 : Algebra
Let and be functions such that , and . Which of the following is equal to ?
If and are defined as inverse functions, then . Thus, according to the definition of inverse functions, and given in the problem must be inverse functions.
If we want to find the inverse of a function, the most straighforward method is usually replacing with , swapping and , and then solving for .
We want to find the inverse of . First, we will replace with .
Next, we will swap and .
Lastly, we will solve for . The equation that we obtain in terms of will be in the inverse of , which equals .
We can treat as a proportion, . This allows us to cross multiply and set the results equal to one another.
We want to get y by itself, so let's divide both sides by x.
Next, we will add 3 to both sides.
To combine the right side, we will need to rewrite 3 so that it has a denominator of .
The answer is .
Example Question #1033 : Algebra
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Example Question #62 : How To Find F(X)
Let the function f be defined by f(x)=x-t. If f(12)=4, what is the value of f(0.5*t)?
First we substitute in 12 for x and set the equation up as 12-t=4. We then get t=8, and substitute that for t and get f(0.5*8), giving us f(4). Plugging 4 in for x, and using t=8 that we found before, gives us:
f(4) = 4 - 8 = -4
Example Question #61 : Algebraic Functions
Which of the following is equal to if ?
To solve, we can set the given function equal to six and solve for .
Add 3 to each side:
Take the square root. Remember that the root can be positive OR negative:
Subtract 3 from each side. It will be easiest to separate the equation into two parts:
Now we know that is equal to or . Based on the available answer options, the correct choice must be .
You can also solve this question by checking each answer option separately; you should find the same final answer.
Substitute each of the answer choices to see which one makes the equation equal to 6.
The answer to this question is . No other answer makes the equation equal 6.