SAT II Math I : SAT Subject Test in Math I

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

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Example Questions

Example Question #83 : Single Variable Algebra

Define a function .

 for exactly one value of  on the interval . Which of the following is true of ?

Possible Answers:

Correct answer:

Explanation:

Define . Then, if , it follows that .

By the Intermediate Value Theorem (IVT), if  is a continuous function, and  and  are of unlike sign, then  for some .  and  are both continuous everywhere, so  is a continuous function, so the IVT applies here.

Evaluate  for each of the following values: 

 

 

 

 

 

 

 

Only in the case of  does it hold that  assumes a different sign at both endpoints - . By the IVT, , and , for some .

Example Question #241 : Sat Subject Test In Math I

Consider the absolute value equation

Which of the following quadratic equations has the same solution set as this one?

Possible Answers:

Correct answer:

Explanation:

The absolute value equation  can be rewritten as the compound equation

   

Each simple equation can be solved by subtracting 7 from both sides:

 

 

The absolute value equation has solution set .

Suppose  is a polynomial. Then, by the Factor Theorem,  is a factor of  if and only if   - that is, if  is a solution of . We are seeking a quadratic equation with solution set the same as that of the absolute value equation, , we want polynomial  to have as its linear binomial factors , or , and 

The correct polynomial will be the product of these two:

Using the FOIL technique to rewrite this:

The correct choice is the equation .

Example Question #84 : Single Variable Algebra

Give the set of all real solutions of the equation  .

Possible Answers:

Correct answer:

Explanation:

Set . Then 

 can be rewritten as

Substituting  for  and  for , the equation becomes 

,

a quadratic equation in .

This can be solved using the  method. We are looking for two integers whose sum is  and whose product is . Through some trial and error, the integers are found to be  and 4, so the above equation can be rewritten, and solved using grouping, as

By the Zero Product Principle, one of these factors is equal to zero:

Either:

Substituting back:

, or 

 

Cubing both sides:

 

Or:

Substituting back:

, or 

Cubing both sides:

.

The solution set is .

Example Question #81 : Single Variable Algebra

Give the set of all real solutions of the equation .

Possible Answers:

Correct answer:

Explanation:

Set . Then 

 can be rewritten as

Substituting  for  and  for , the equation becomes 

,

a quadratic equation in .

This can be solved using the  method. We are looking for two integers whose sum is  and whose product is . Through some trial and error, the integers are found to be  and 4, so the above equation can be rewritten, and solved using grouping, as

By the Zero Product Principle, one of these factors is equal to zero:

Either:

Substituting back:

 

However, there are no real numbers whose squares are negative. Since we are looking only for real solutions, none are yielded here.

 

Or:

Substituting back:

Taking both square roots of both sides and simplifying using the Quotient of Radicals Rule:

The solution set is .

Example Question #82 : Single Variable Algebra

Define a function .

 for exactly one value of  on the interval . Which of the following is true of 

Possible Answers:

Correct answer:

Explanation:

Define . Then, if , it follows that .

By the Intermediate Value Theorem (IVT), if  is a continuous function, and  and  are of unlike sign, then  for some . As a polynomial,  is a continuous function, so the IVT applies here. 

Evaluate  for each of the following values: :

Only in the case of  does it hold that  assumes different signs at the endpoints - . By the IVT, , and , for some .

Example Question #241 : Sat Subject Test In Math I

Solve:  

Possible Answers:

Correct answer:

Explanation:

Subtract 18 on both sides.

Divide by three on both sides.

The answer is:  

Example Question #87 : Single Variable Algebra

Solve the equation:  

Possible Answers:

Correct answer:

Explanation:

Subtract seven from both sides.

Divide both sides by negative nine.

The answer is:  

Example Question #91 : Single Variable Algebra

Solve the equation:  

Possible Answers:

Correct answer:

Explanation:

Add  on both sides of the equation.

Subtract 18 on both sides of the equation.

The answer is:  

Example Question #91 : Single Variable Algebra

Solve the following equation:  

Possible Answers:

Correct answer:

Explanation:

Multiply both sides by the least common denominator .  This will eliminate the fractions on both sides of the equation.

Subtract 4 on both sides.

Divide by 24 on both sides.

The answer is:  

Example Question #92 : Single Variable Algebra

    

Possible Answers:

Correct answer:

Explanation:

A cubic polynomial has three zeroes, if a zero of multiplicity  is counted  times. Since its lead term is , we know that

where , and  are its zeroes.

 , so 3 and 5 are zeroes of , and, by the Factor Theorem,  and  are among the linear factors - that is,

for some .

However, we are not given the multiplicity of either 3 or 5, so we do not know which, if either, of the two are equal to . Without this information, we cannot determine  for certain.

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