ISEE Upper Level Quantitative : Equations

Study concepts, example questions & explanations for ISEE Upper Level Quantitative

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Example Questions

Example Question #121 : How To Find The Solution To An Equation

If  is negative and , then what is  ?

Possible Answers:

The equation has no negative solution.

Correct answer:

Explanation:

, so either

 or 

We solve both equations separately:

 

 

 

Since the negative solution is being requested, we choose .

Example Question #122 : How To Find The Solution To An Equation

Give the solution set of the equation:

Possible Answers:

Correct answer:

Explanation:

Either

 or ,

so we solve the equations separately:

 

 

or

 

 

The solution set is 

Example Question #121 : How To Find The Solution To An Equation

Which of the folllowing is a true statement?

Possible Answers:

The equation has three solutions.

The equation has no solution.

The equation has infinitely many solutions.

The equation has one solution.

The equation has two solutions.

Correct answer:

The equation has infinitely many solutions.

Explanation:

Since the absolute value of a nonnegative number is the number itself, and the absolute value of a negative number is its (positive) opposite, we have to examine up to three cases:  , , and .

 

However, let us examine that third case. 

This makes  and  negative, so the equation can be rewritten:

This statement is identically true. Therefore, all values of  less than  work, and we have already proved that there are infinitely many solutions. We do not need to go further.

 

Example Question #124 : How To Find The Solution To An Equation

Which of the following is a true statement?

Possible Answers:

Correct answer:

Explanation:

,

so 

 

 

 

Using two substitutions:

 

The correct choice is .

Example Question #125 : How To Find The Solution To An Equation

Which of the following is a true statement?

Possible Answers:

Correct answer:

Explanation:

 

Similarly,

 

 

By substitution:

Example Question #126 : How To Find The Solution To An Equation

Express  in terms of .

Possible Answers:

Correct answer:

Explanation:

Example Question #122 : How To Find The Solution To An Equation

Which of the following is true of  ?

Possible Answers:

Correct answer:

Explanation:

Example Question #123 : How To Find The Solution To An Equation

Which of the following is true of  ?

Possible Answers:

None of the other responses gives a correct answer.

Correct answer:

Explanation:

Example Question #124 : How To Find The Solution To An Equation

Function 4

Define  to be the function graphed in the figure above, and 

Evaluate 

Possible Answers:

 is outside the domain of 

Correct answer:

Explanation:

From the diagram below, it can be seen that .

Function 4a

, so

Therefore, 

.

Example Question #125 : How To Find The Solution To An Equation

Function 4

Define  to be the function graphed in the figure above, and 

Evaluate 

Possible Answers:

 is outside the domain of 

Correct answer:

Explanation:

 

 

.

Examine the diagram below.

Function 4a

As can be seen, . Therefore, .

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