Mathematical Relationships - SAT Subject Test in Math I

Card 0 of 20

Question

Define an operation on the set of real numbers as follows:

For any two real numbers

Evaluate the expression

Answer

Substitute in the expression:

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Question

Solve for .

Answer

To solve for x we need to make two separate equations. Since it has absolute value bars around it we know that the inside can equal either 7 or -7 before the asolute value is applied.

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Question

Simplify the following expression:

Answer

To simplify, we must first simplify the absolute values.

Now, combine like terms:

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Question

The absolute value of a negative can be positive or negative. True or false?

Answer

The absolute value of a number is the points away from zero on a number line.

Since this is a countable value, you cannot count a negative number.

This makes all absolute values positive and also make the statement above false.

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Question

Consider the quadratic equation

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

Answer

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

Factor this as

where the squares represent two integers with sum and product 14. Through some trial and error, we find that and work:

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

If then ;

if then .

The given 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 .

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Question

What is the value of: ?

Answer

Step 1: Evaluate ...

Step 2: Apply the minus sign inside the absolute value to the answer in Step 1...

Step 3: Define absolute value...

The absolute value of any value is always positive, unless there is an extra negation outside (sometimes)..

Step 4: Evaluate...

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Question

Solve:

Answer

Divide both sides by negative three.

Since the lone absolute value is not equal to a negative, we can continue with the problem. Split the equation into its positive and negative components.

Evaluate the first equation by subtracting one on both sides, and then dividing by two on both sides.

Evaluate the second equation by dividing a negative one on both sides.

Subtract one on both sides.

Divide by 2 on both sides.

The answers are:

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Question

Evaluate the expression.

Answer

Follow the correct order of operations: parenthenses, exponents, multiplication, division, addition, subtraction.

First, evaluate any terms in parenthesis.

Next, evaluate the exponent.

Divide.

Finally, add.

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Question

Evalute the expression:

Answer

Follow the correct order of operations: parentheses, exponents, multiplication, division, addition, subtraction. (This is typically abbreviated as PEMDAS. Note that both multiplication and division, and addition and subtraction, are equal to each other in terms of rank, so when both are present, solving the equation proceeds from left to right).

First, simplify anything in parentheses.

Next, simplify any terms with exponents.

Now, perform multiplication.

Since all we are left with is addition and subtraction, we perform simplification from left to right.

Thus, our answer is:

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Question

Add in modulo 7:

Answer

In modulo 7 arithmetic, a number is congruent to the remainder of its division by 7.

Therefore, since and ,

,

and the correct response is 3.

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Question

Add:

Answer

To solve , make sure the digits are aligned with the correct placeholder. It is also possible to add term by term.

The correct answer is:

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Question

Evaluate: .

Answer

Step 1: Recall PEMDAS...

Parentheses, Exponents, Multiplication, Division, Addition, Subtraction.

Step 2: Perform the evaluation in separate pieces...

Step 3: Replace the values and keep the signs..

Step 4: Evaluate:

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Question

Find the sum of the numbers:

Answer

Add all the ones digits.

Add the tens digits with the two as the carryover.

Combine this value with the ones digit of the first number.

The answer is:

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Question

Evaluate:

Answer

Add the ones digits.

Add the tens digits with the tens digit of the previous number as carryover.

Repeat the process with the hundreds digits.

Combine this number with the ones digits of the previous calculations.

The answer is:

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Question

Rewrite as a single logarithmic expression:

Answer

Using the properties of logarithms

and ,

we simplify as follows:

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Question

How many elements are in a set that has exactly 128 subsets?

Answer

A set with elements has subsets.

Solve:

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Question

Solve:

Answer

In order to solve this problem, covert 27 to the correct base and power.

Since , the correct answer is .

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Question

Simplify

Answer

When an exponent is raised by another exponent, we just multiply the powers.

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Question

Simplify:

Answer

When adding exponents, we don't add the exponents or multiply out the bases. Our goal is to see if we can factor anything. We do see three . Let's factor.

Remember when multiplying exponents, we just add the powers.

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Question

Solve and simplify.

Answer

Another way to write this is . The only number that makes is .

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