ISEE Upper Level Quantitative : Variables and Exponents

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

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Example Questions

Example Question #1 : How To Find The Exponent Of Variables

Expand: 

Which is the greater quantity?

(a) The coefficient of 

(b) The coefficient of 

Possible Answers:

It is impossible to tell from the information given.

(b) is greater.

(a) is greater.

The two quantities are equal.

Correct answer:

(b) is greater.

Explanation:

Using the Binomial Theorem, if  is expanded, the  term is 

.

This makes  the coefficient of .

We compare the values of this expression at  for both  and .

 

(a)  If  and , the coefficient is 

.

This is the coefficient of .

(b) If  and , the coefficient is 

.

This is the coefficient of .

(b) is the greater quantity.

Example Question #3 : How To Find The Exponent Of Variables

Consider the expression 

Which is the greater quantity?

(a) The expression evaluated at 

(b) The expression evaluated at 

Possible Answers:

(b) is greater

(a) is greater

It is impossible to tell from the information given

(a) and (b) are equal

Correct answer:

(b) is greater

Explanation:

Use the properties of powers to simplify the expression:

(a) If , then 

(b) If , then 

(b) is greater.

Example Question #4 : How To Find The Exponent Of Variables

Which of the following expressions is equivalent to 

 ?

Possible Answers:

None of the other answers is correct.

Correct answer:

None of the other answers is correct.

Explanation:

Use the square of a binomial pattern as follows:

This expression is not equivalent to any of the choices.

Example Question #3 : How To Find The Exponent Of Variables

Express   in terms of .

Possible Answers:

Correct answer:

Explanation:

 

, so

 

, so 

Example Question #11 : Variables And Exponents

. Which is the greater quantity?

(a) 

(b) 

Possible Answers:

(b) is the greater quantity

It is impossible to determine which is greater from the information given

(a) and (b) are equal

(a) is the greater quantity

Correct answer:

(a) is the greater quantity

Explanation:

By the Power of a Power Principle, 

Therefore, 

It follows that 

Example Question #911 : Isee Upper Level (Grades 9 12) Quantitative Reasoning

 is a real number such that . Which is the greater quantity?

(a) 

(b) 11

Possible Answers:

(b) is the greater quantity

(a) and (b) are equal

(a) is the greater quantity

It is impossible to determine which is greater from the information given

Correct answer:

It is impossible to determine which is greater from the information given

Explanation:

By the Power of a Power Principle, 

 

Therefore,  is a square root of 121, of which there are two - 11 and . Since it is possible for a third (odd-numbered) power of a real number to be positive or negative, we cannot eliminate either possibility, so either

or 

.

Therefore, we cannot determine whether  is less than 11 or equal to 11.

Example Question #912 : Isee Upper Level (Grades 9 12) Quantitative Reasoning

Possible Answers:

Correct answer:

Explanation:

By the Power of a Product Principle, 

Also, by the Power of a Power Principle

Therefore, 

Example Question #12 : Variables And Exponents

 is a negative number. Which is the greater quantity?

(a) 

(b) 

Possible Answers:

It is impossible to determine which is greater from the information given

(a) is the greater quantity

(a) and (b) are equal

(b) is the greater quantity

Correct answer:

(b) is the greater quantity

Explanation:

Any nonzero number raised to an even power, such as 4, is a positive number. Therefore, 

 is the product of a negative number and a positive number, and is therefore negative. 

By the same reasoning,   is a positive number.

It follows that .

Example Question #914 : Isee Upper Level (Grades 9 12) Quantitative Reasoning

Evaluate .

Possible Answers:

Correct answer:

Explanation:

By the Power of a Power Principle,

By way of the Power of a Quotient Principle, 

.

Example Question #915 : Isee Upper Level (Grades 9 12) Quantitative Reasoning

 and  are both real numbers.

Evaluate .

Possible Answers:

Correct answer:

Explanation:

, as the product of a sum and a difference, can be rewritten using the difference of squares pattern:

By the Power of a Power Principle, 

Therefore,  is a square root of  - that is, a square root of 121. 121 has two square roots,  and 121, but since  is real,  must be the positive choice, 11. Similarly,  is the positive square root of 81, which is 9.

The above expression can be evaluated as

.

 

 

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