SAT II Math II : Mathematical Relationships

Study concepts, example questions & explanations for SAT II Math II

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Example Questions

Example Question #5 : Absolute Value

Define .

How many values are in the solution set of the equation  ?

Possible Answers:

Three solutions

One solution

Infinitely many solutions

Two solutions

No solutions

Correct answer:

No solutions

Explanation:

We can rewrite this function as a piecewise-defined function by examining three different intervals of -values.

If , then 

 and ,

and this part of the function can be written as

If  under this definition, then 

However, , so this is a contradiction.

 

If , then 

 and ,

and this part of the function can be written as

This yields no solutions.

 

If , then 

 and ,

and this part of the function can be written as

If  under this definition, then 

However, , so this is a contradiction.

 

 has no solution.

Example Question #6 : Absolute Value

Define .

How many values are in the solution set of the equation  ?

Possible Answers:

Infinitely many solutions

No solutions

One solution

Two solutions

Three solutions

Correct answer:

Infinitely many solutions

Explanation:

We can rewrite this function as a piecewise-defined function by examining three different intervals of -values.

If , then 

 and ,

and this part of the function can be written as

 

If , then 

 and ,

and this part of the function can be written as

 

If , then 

 and ,

and this part of the function can be written as

 

The function can be rewritten as

As can be seen from the rewritten definition, every value of  in the interval  is a solution of , so the correct response is infinitely many solutions.

Example Question #7 : Absolute Value

Consider the quadratic equation 

Which of the following absolute value equations has the same solution set?

Possible Answers:

None of the other choices gives the correct response.

Correct answer:

Explanation:

Rewrite the quadratic equation in standard form by subtracting  from both sides:

Solve this equation using the  method. We are looking for two integers whose sum is  and whose product is ; by trial and error we find they are . The equation becomes

Solving using grouping:

By the Zero Product Principle, one of these factors must be equal to 0. 

Either

Or

The given quadratic equation has solution set , so we are looking for an absolute value equation with this set as well.

This equation can take the form

This can be rewritten as the compound equation

   

Adding  to both sides of each equation, the solution set is 

 and 

Setting these numbers equal in value to the desired solutions, we get the linear system

Adding and solving for :

      

Backsolving to find :

The desired absolute value equation is .

 

Example Question #1 : Absolute Value

Solve .

Possible Answers:

Correct answer:

Explanation:

First we need to isolate the absolute value term.  We do with using some simple algebra:

Now we solve two equations, one with the right side of the equation positive, one negative.  Let's start with the positive:

And now the negative:

So our answers are:

Example Question #1 : Absolute Value

Solve .

Possible Answers:

No solutions

Correct answer:

No solutions

Explanation:

First, we have to isolate the absolute value:

Let's take a look at our equation right now.  It's saying that the absolute value has to be a negative number, which isn't possible.  So no solutions exist.

Example Question #41 : Mathematical Relationships

Solve .

Possible Answers:

No solutions

Correct answer:

Explanation:

First, we need to isolate the absolute value:

Because the equation is set equal to , we can drop the absolute value symbols and solve normally:

Example Question #41 : Mathematical Relationships

Solve:  

Possible Answers:

Correct answer:

Explanation:

Add 3 on both sides.

Divide by 25 on both sides.

Recall that an absolute value cannot have a negative value.  There is no x-value that will equal to the right term.

The answer is:  

Example Question #42 : Mathematical Relationships

Solve: .

Possible Answers:

 or 

Correct answer:

Explanation:

Because the absolute value term is "less than" the other side of the equation, we can rewrite the problem like this:

This eliminates the absolute value.  Remember, when an operation is performed, it must be performed on all three sets of terms.  When we add  to each side, we end up with:

Example Question #41 : Mathematical Relationships

Solve: 

Possible Answers:

 or 

Correct answer:

 or 

Explanation:

Here, we have to split the problem up into two parts:

 and 

Let's start with the first equation:

First, we can add  to each side:

Now we divide by -6.  Remember, when you divide by a negative, you flip the sign of the inequality:

Which we can reduce:

Now let's do the other part of the problem the same way:

Example Question #11 : Absolute Value

Give the solution set of the inequality:

Possible Answers:

All real numbers

Correct answer:

All real numbers

Explanation:

To solve an absolute value inequality, first isolate the absolute value expression, which can be done here by subtracting 35 from both sides:

There is no need to go further. The absolute value of any number is always greater than or equal to 0, so, regardless of the value of ,

.

Therefore, the solution set is the set of all real numbers.

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