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

Which is the greater quantity?

(a) 

(b) 37 

Possible Answers:

(b) is the greater quantity

(a) is the greater quantity

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

(a) and (b) are equal

Correct answer:

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

Explanation:

Multiply the polynomials through distribution:

The absolute value of  is 4, so either  or . Likewise,  or 

If  and , we see that 

If  and , we see that 

In the first scenario, ; in the second, . This makes the information insufficient.

Example Question #17 : How To Find The Exponent Of Variables

Which is the greater quantity?

(a) 

(b) 

Possible Answers:

(a) and (b) are equal

(b) is the greater quantity

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

(a) is the greater quantity

Correct answer:

(a) is the greater quantity

Explanation:

The absolute value of  is 4, so either  or . Likewise,  or . However, since  and , it follows that regardless,  and .

As the product of the sum and the difference of the same two expressions,  can be rewritten as the difference of the squares of the expressions:

Using the Power of a Product Principle:

Substituting, 

Similarly,

Therefore, .

Example Question #21 : Variables And Exponents

Which is the greater quantity?

(a) 

(b) 16

Possible Answers:

(a) and (b) are equal

(a) is the greater quantity

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

(b) is the greater quantity

Correct answer:

(b) is the greater quantity

Explanation:

Multiply the polynomials through distribution:

Collecting like terms, the above becomes

By the Power of a Power Principle, 

This makes  a square root (positive or negative) of , or 81, so 

or

We can not eliminate either since an odd power of a number can have any sign, and we are not given the sign of .

By similar reasoning, either

or 

 can assume one of four values, depending on which values of  and  are selected:

Regardless of the choice of  and .

 

Example Question #71 : Variables

Define 

 is a function with the set of all real numbers as its domain.

Which is the greater quantity?

(a) 

(b) 

Possible Answers:

(b) is the greater quantity

(a) is the greater quantity

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

(a) and (b) are equal

Correct answer:

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

Explanation:

, so .

By definition, 

.

Since  and , we can determine that 

.

However, this does not tell us the value of  at . Therefore, we do not know whether  or , if either, is the greater.

Example Question #21 : Variables And Exponents

Simplify the expression:

Possible Answers:

 

The expression cannot be simplified further.

Correct answer:

 

Explanation:

Group, then collect like terms.

Example Question #2 : How To Subtract Exponential Variables

Assume neither  nor  is zero.

Which is the greater quantity?

(a)  

(b)

Possible Answers:

It is impossible to tell from the information given.

(a) and (b) are equal.

(a) is greater.

(b) is greater.

Correct answer:

(a) and (b) are equal.

Explanation:

Simplify the expression in (a):

 regardless of the values of the variables, and (a) and (b) are equal.

Example Question #1 : How To Subtract Exponential Variables

 is a positive number.  is a negative number.

Which is the greater quantity?

(a) 

(b) 

Possible Answers:

(a) and (b) are equal.

It is impossible to tell from the information given.

(a) is greater.

(b) is greater.

Correct answer:

(b) is greater.

Explanation:

 is a positive number and  is a negative number, so  and . Therefore,

.

(b) is always greater.

Example Question #1 : How To Multiply Exponential Variables

Simplify:

Possible Answers:

Correct answer:

Explanation:

Example Question #2 : How To Multiply Exponential Variables

Expand: 

Possible Answers:

Correct answer:

Explanation:

A binomial can be cubed using the pattern:

Set 

Example Question #82 : Variables

Factor completely:

Possible Answers:

Correct answer:

Explanation:

A trinomial whose leading term has a coefficent other than 1 can be factored using the -method. We split the middle term using two numbers whose product is  and whose sum is . These numbers are , so:

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