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Example Questions
Example Question #986 : Psat Mathematics
If , what is the smallest possible value of
?
4
6
8
12
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 #61 : Algebraic Functions
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 #62 : Algebraic Functions
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 #987 : Psat Mathematics
.
Example Question #989 : Psat Mathematics
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 #63 : 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.
Example Question #331 : Algebra
If is an odd integer, and
is an even integer, which of the following must be even?
Solve this problem using picked numbers. Choose an odd number to represent and an even number to represent
. In this case, we have chosen 3 to represent
and 2 to represent
.
Substitute into each equation to find the correct answer:
This number is even, and likely the answer we are looking for. Just in case, quickly check the other answers to make sure no others come out even.
This expression gives an odd answer and must be incorrect.
This expression gives an odd answer and must be incorrect.
This expression gives an odd answer and must be incorrect.
This expression gives an odd answer and must be incorrect.
Only the first answer is even. The answer is .
Example Question #72 : How To Find F(X)
If
What is ?
To find f(4), input a 4 in every place you see an x in the equation. That gives you
When you simplify this expression, you get
When you add together each part, you get
Example Question #332 : Algebra
What is the value of the function f(x) = 6x2 + 16x – 6 when x = –3?
0
–108
–12
96
0
There are two ways to do this problem. The first way just involves plugging in –3 for x and solving 6〖(–3)〗2 + 16(–3) – 6, which equals 54 – 48 – 6 = 0. The second way involves factoring the polynomial to (6x – 2)(x + 3) and then plugging in –3 for x. The second way quickly shows that the answer is 0 due to multiplying by (–3 + 3).
Example Question #35 : Algebraic Functions
Given the functions f(x) = 2x + 4 and g(x) = 3x – 6, what is f(g(x)) when x = 6?
192
16
12
28
144
28
We need to work from the inside to the outside, so g(6) = 3(6) – 6 = 12.
Then f(g(6)) = 2(12) + 4 = 28.
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