Algebra II : Basic Single-Variable Algebra

Study concepts, example questions & explanations for Algebra II

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Example Questions

Example Question #21 : Expressions

Write the expression:  The product of three more than six times a number and two less than the same number. 

Possible Answers:

\(\displaystyle (6x+3)(x-2)\)

\(\displaystyle (6x+3)(6x-1)\)

\(\displaystyle (6x+3)(6x+1)\)

\(\displaystyle 6x-1\)

\(\displaystyle 6(x-2)+3\)

Correct answer:

\(\displaystyle (6x+3)(x-2)\)

Explanation:

Let the unknown number be \(\displaystyle x\).

Three more than six times a number:  \(\displaystyle 6x+3\)

Two less than the same number:  \(\displaystyle x-2\)

The "and" would separate the quantities and the product would be:  

\(\displaystyle (6x+3)(x-2)\)

The answer is:  \(\displaystyle (6x+3)(x-2)\)

Example Question #22 : Expressions

Set up the expression:  The cube root of two times a number squared.

Possible Answers:

\(\displaystyle \sqrt[3]{2x^2}\)

\(\displaystyle 4\sqrt[3]{x^2}\)

\(\displaystyle 2\sqrt[3]{x^2}\)

\(\displaystyle (2x)^{\frac{3}{2}}\)

\(\displaystyle \sqrt[3]{4x^2}\)

Correct answer:

\(\displaystyle \sqrt[3]{2x^2}\)

Explanation:

Solve this question by first writing the inner quantity of the cube root.

Two times a number squared:  \(\displaystyle 2x^2\)

The cube root of two times a number squared:  \(\displaystyle \sqrt[3]{2x^2}\)

The answer is:  \(\displaystyle \sqrt[3]{2x^2}\)

Example Question #23 : Expressions

Set up the expression:  Five times the fifth root of three times a number.

Possible Answers:

\(\displaystyle 5(3x)^5\)

\(\displaystyle \sqrt[5]{15x}\)

\(\displaystyle \sqrt[5]{5(3x)^5}\)

\(\displaystyle 5\sqrt[5]{3x}\)

\(\displaystyle 5\sqrt[5]{3x^5}\)

Correct answer:

\(\displaystyle 5\sqrt[5]{3x}\)

Explanation:

Split the statement into parts.

Three times a number:  \(\displaystyle 3x\)

The fifth root of three times a number:  \(\displaystyle \sqrt[5]{3x}\)

Five times the fifth root of three times a number:  \(\displaystyle 5\sqrt[5]{3x}\)

The answer is:  \(\displaystyle 5\sqrt[5]{3x}\)

Example Question #24 : Expressions

Set up the expression:  Nine times the quantity of five times a number less than five.

Possible Answers:

\(\displaystyle y< 9(5-5x)\)

\(\displaystyle 9(5x-5)\)

\(\displaystyle 9(5x)< 5\)

\(\displaystyle (5x)^9-5\)

\(\displaystyle 9(5-5x)\)

Correct answer:

\(\displaystyle 9(5-5x)\)

Explanation:

An expression cannot contain an equal sign or inequality sign.

Start with the quantity.

Five times a number less than five:  \(\displaystyle 5-5x\)

Nine times the quantity of five times a number less than five:  \(\displaystyle 9(5-5x)\)

The answer is:  \(\displaystyle 9(5-5x)\)

Example Question #25 : Expressions

Set up the following expression:  The fifth root of the quantity of six less than twice a number.

Possible Answers:

\(\displaystyle 2\sqrt[5]{x-6}\)

\(\displaystyle \sqrt[5]{2x-6}\)

\(\displaystyle 2\sqrt[5]{x}-6\)

\(\displaystyle \sqrt[5]{2x}-6\)

\(\displaystyle \sqrt[5]{2(x-6)}\)

Correct answer:

\(\displaystyle \sqrt[5]{2x-6}\)

Explanation:

Break up the sentence into parts.

The quantity of six less than twice a number:  \(\displaystyle 2x-6\)

The fifth root of the quantity of six less than twice a number:  \(\displaystyle \sqrt[5]{2x-6}\)

The answer is:  \(\displaystyle \sqrt[5]{2x-6}\)

Example Question #31 : Expressions

Set up the expression:  The square of the difference of twice a number and six.

Possible Answers:

\(\displaystyle (2x-6)^2\)

\(\displaystyle (2x)^2-6\)

\(\displaystyle (2[x-6])^2\)

\(\displaystyle \sqrt{2x-6}\)

\(\displaystyle \sqrt{2x}-6\)

Correct answer:

\(\displaystyle (2x-6)^2\)

Explanation:

Start by taking the difference of the two numbers.

The difference of twice a number and six:  \(\displaystyle 2x-6\)

The square of the difference of twice a number and six:  \(\displaystyle (2x-6)^2\)

Be careful not to mix the terms of square and square root.

The answer is:  \(\displaystyle (2x-6)^2\)

Example Question #31 : Expressions

Set up the expression:  The fourth root of the quantity of three less than five times a number.

Possible Answers:

\(\displaystyle 5\sqrt[4]{x-3}\)

\(\displaystyle \sqrt[4]{5(x-3)}\)

\(\displaystyle \sqrt[4]{3-5x}\)

\(\displaystyle (5x-3)^4\)

\(\displaystyle \sqrt[4]{5x-3}\)

Correct answer:

\(\displaystyle \sqrt[4]{5x-3}\)

Explanation:

Start with the quantity.

Three less than five times a number:  \(\displaystyle 5x-3\)

This term is a quantity.

The fourth root of the quantity:  \(\displaystyle \sqrt[4]{5x-3}\)

The answer is:  \(\displaystyle \sqrt[4]{5x-3}\)

Example Question #32 : Expressions

Set up the expression:  The sum of twice a number and three times another number cubed is eight. 

Possible Answers:

\(\displaystyle (5x)^3 = 8\)

\(\displaystyle (2x+3y)^3 = 8\)

\(\displaystyle 5x^3 = 8\)

\(\displaystyle 2x+(3y)^3 = 8\)

\(\displaystyle 2x+3y^3 = 8\)

Correct answer:

\(\displaystyle 2x+3y^3 = 8\)

Explanation:

Break up the terms and write each part.

Twice a number:  \(\displaystyle 2x\)

Three times another number cubed:  \(\displaystyle 3y^3\)

Is eight:  \(\displaystyle =8\)

Sum the two different numbers that is equal to eight.

The answer is:  \(\displaystyle 2x+3y^3 = 8\)

Example Question #33 : Expressions

Set up the expression:  The fourth root of twice a number squared.

Possible Answers:

\(\displaystyle \sqrt{2x}\)

\(\displaystyle \sqrt[4]{(2x)^2}\)

\(\displaystyle \sqrt[4]{2x^2}\)

\(\displaystyle x^2\sqrt[4]{2}\)

\(\displaystyle 2\sqrt[4]{x^2}\)

Correct answer:

\(\displaystyle \sqrt[4]{2x^2}\)

Explanation:

Break up the sentence into parts.

Twice a number squared:  \(\displaystyle 2x^2\)

The fourth root of twice a number squared:  \(\displaystyle \sqrt[4]{2x^2}\)

Do not mix split this radical and pull out the coefficient!

The answer is:  \(\displaystyle \sqrt[4]{2x^2}\)

Example Question #32 : Expressions

Set up the following expression:  Five less than eight times the cube of a number is negative eleven.

Possible Answers:

\(\displaystyle 8x^3-5 =-11\)

\(\displaystyle 8(x-5)^3 =-11\)

\(\displaystyle 8(x^3-5) =-11\)

\(\displaystyle 5-8x^3 =-11\)

\(\displaystyle 8x^3-5 =11\)

Correct answer:

\(\displaystyle 8x^3-5 =-11\)

Explanation:

Split the sentence into parts.

The cube of a number:  \(\displaystyle x^3\)

Eight times the cube of a number:  \(\displaystyle 8x^3\)

Five less than eight times the cube of a number:  \(\displaystyle 8x^3-5\)

Is negative eleven:  \(\displaystyle =-11\)

The answer is:  \(\displaystyle 8x^3-5 =-11\)

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