Algebra II : Algebra II

Study concepts, example questions & explanations for Algebra II

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Example Questions

Example Question #91 : Understanding Radicals

Solve:  \displaystyle -16^{-\frac{3}{4}}

Possible Answers:

\displaystyle -\frac{1}{8}

\displaystyle \frac{1}{8}

\displaystyle -\frac{1}{4}

\displaystyle \frac{1}{4}

\displaystyle -\frac{1}{16}

Correct answer:

\displaystyle -\frac{1}{8}

Explanation:

We will need to rewrite the negative exponent as a fraction.

\displaystyle -16^{-\frac{3}{4}} = -\frac{1}{16^{\frac{3}{4}}}

Recall that the denominator of the power represents the root index, and the numerator of the power represents what the quantity is raised to.

\displaystyle 16^{\frac{3}{4}} =( \sqrt[4]{16})^3 = (2)^3 = 8

Replace the denominator.

\displaystyle -\frac{1}{16^{\frac{3}{4}}} = -\frac{1}{8}

The answer is:  \displaystyle -\frac{1}{8}

Example Question #1321 : Mathematical Relationships And Basic Graphs

Solve:  \displaystyle 27^\frac{1}{3}-16^{\frac{1}{2}}

Possible Answers:

\displaystyle -\frac{1}{4}

\displaystyle 1

\displaystyle -\frac{1}{3}

\displaystyle -1

\displaystyle -3

Correct answer:

\displaystyle -1

Explanation:

The denominator of the fractional exponent represents the index of the radical.

Rewrite the expression in radical form.  A radical with an index of 2 is simply the square root of a number.

\displaystyle 27^\frac{1}{3}-16^{\frac{1}{2}} = \sqrt[3]{27}-\sqrt{16} = 3-4 = -1

The answer is:  \displaystyle -1

Example Question #3991 : Algebra Ii

What is \displaystyle 125^\frac{7}{3} equivalent to?

Possible Answers:

\displaystyle (\frac{1}{5})^7

\displaystyle 5^7

\displaystyle \textup{The answer is not given.}

\displaystyle (\frac{3}{5})^7

\displaystyle (\frac{5}{3})^7

Correct answer:

\displaystyle 5^7

Explanation:

The denominator represents the index of the square root.  The numerator is the  power that the quantity is raised to.

Rewrite the expression as a radical.

\displaystyle 125^\frac{7}{3} =( \sqrt[3]{125})^7 = 5^7

The answer is:  \displaystyle 5^7

Example Question #1 : Factoring Radicals

Simplify the expression:

\displaystyle \frac{3\sqrt[4]{32}}{2\sqrt[4]{162}}

Possible Answers:

.\displaystyle \frac{3\sqrt[4]{16}}{2\sqrt[4]{81}}

\displaystyle \frac{3}{2}

\displaystyle \frac{2}{3}

\displaystyle 1

\displaystyle 6\sqrt[4]{2}

Correct answer:

\displaystyle 1

Explanation:

Use the multiplication property of radicals to split the fourth roots as follows:

\displaystyle \rightarrow \frac{3\sqrt[4]{16}\sqrt[4]{2}}{2\sqrt[4]{81}\sqrt[4]{2}}

Simplify the new roots:

\displaystyle \rightarrow \frac{3(2)\sqrt[4]{2}}{2(3)\sqrt[4]{2}}

\displaystyle \rightarrow \frac{6\sqrt[4]{2}}{6\sqrt[4]{2}}

\displaystyle \rightarrow 1

Example Question #2 : Factoring Radicals

Simplify the expression.

\displaystyle \sqrt{300x^{3}}

Possible Answers:

\displaystyle x\sqrt{300x}

\displaystyle 5x\sqrt{12x}

\displaystyle 10x\sqrt{3x}

\displaystyle 2x\sqrt{75x}

\displaystyle 10\sqrt{3x^{3}}

Correct answer:

\displaystyle 10x\sqrt{3x}

Explanation:

Use the multiplication property of radicals to split the perfect squares as follows:

\displaystyle \sqrt{100}\sqrt{3}\sqrt{x^{2}}\sqrt{x}

Simplify roots,

\displaystyle 10\sqrt{3}\ast x\sqrt{x} = 10x\sqrt{3x}

 

Example Question #3 : Factoring Radicals

Simplify the radical \displaystyle \sqrt{12}.

Possible Answers:

\displaystyle 2\sqrt{3}

\displaystyle 3\sqrt{2}

\displaystyle 4\sqrt{3}

\displaystyle 2\sqrt{6}

None of the other answers

Correct answer:

\displaystyle 2\sqrt{3}

Explanation:

To simplify radicals, we need to factor the expression inside the radical. A radical can only be simplified if one of the factors has a square root that is an integer.

For this problem, we'll first find all of the possible radicals of 12: 1 & 12, 2 & 6, and 3 & 4. Then we look at each factor and determine if any of them has a square root that is an integer. The only one that does is 4, which has a square root of 2. We can rewrite the radical as \displaystyle \sqrt{3\cdot 4} which can also be written as \displaystyle \sqrt{3}\cdot \sqrt{4}. Taking the squareroot of 4, we come to the answer: \displaystyle 2\sqrt{3}.

Example Question #2 : Simplifying Radicals

Simplify the following expression involving radicals by factoring the radicands:

\displaystyle 4\sqrt{75}-2\sqrt{147}+\sqrt{12}

Possible Answers:

\displaystyle 8\sqrt{3}

\displaystyle 20\sqrt{3}+6\sqrt{2}

\displaystyle 8\sqrt{2}+4\sqrt{7}

\displaystyle 6\sqrt{10}

\displaystyle 2\sqrt{5}

Correct answer:

\displaystyle 8\sqrt{3}

Explanation:

In order to simplify each radical, we must find the factors of its radicand that have a whole number as a square root, which will allow us to take the square root of that factor out of the radical. We start by factoring each radicand, looking for any factors that have a neat whole number as a square root:

\displaystyle 4\sqrt{75}-2\sqrt{147}+\sqrt{12}=4\sqrt{3\cdot25}-2\sqrt{3\cdot49}+\sqrt{3\cdot4}

After factoring each radicand, we can see that there is a perfect square in each: 25 in the first, 49 in the second, and 4 in the third. Because these factors are perfect squares, we can easily take their square root out of the radical, which then gets multiplied by the coefficient already in front of the radical:

\displaystyle 4(5\sqrt{3})-2(7\sqrt{3})+(2\sqrt{3})=20\sqrt{3}-14\sqrt{3}+2\sqrt{3}

After simplifying each radical, we're left with the same value of \displaystyle \sqrt{3} in each term, so we can now add all of our like terms together to completely simplify the expression:

\displaystyle 20\sqrt{3}-14\sqrt{3}+2\sqrt{3}=8\sqrt{3}

Example Question #5 : Simplifying Radicals

Simplify the radical expression.

\displaystyle \sqrt[3]{64x^5y^8z^6}

Possible Answers:

\displaystyle 4xy^2z^2\sqrt[3]{x^2y^2}

\displaystyle 4x^2y^2z^2\sqrt[3]{x^2y^2}

\displaystyle 4x^3y^6z^6\sqrt[3]{x^2y^2}

\displaystyle 4xy^2z^2\sqrt{x^2y^2}

\displaystyle 8x^2y^4z^3\sqrt[3]{x}

Correct answer:

\displaystyle 4xy^2z^2\sqrt[3]{x^2y^2}

Explanation:

In order to solve this equation, we must see how many perfect cubes we can simplify in each radical.

\displaystyle \sqrt[3]{64x^5y^8z^6}

First, let's simplify the coefficient under the radical. \displaystyle 64 is the perfect cube of \displaystyle 4. Therefore, we can remove \displaystyle 64 from under the radical, and what we have instead is:

\displaystyle 4\sqrt[3]{x^5y^8z^6}

Now, in order to remove variables from underneath the square root symbol, we need to remove the variables by the cube. Since radicals have the property

\displaystyle \sqrt{x^2}=\sqrt{x}\cdot\sqrt{x}

we can see that

\displaystyle 4\sqrt[3]{x^5y^8z^6}=4\sqrt[3]{x^3x^2y^6y^2z^6}

With the expression in this form, it is much easier to see that we can remove one cube from \displaystyle x, two cubes from \displaystyle y, and two cubes from \displaystyle z, and therefore our solution is:

\displaystyle 4xy^2z^2\sqrt[3]{x^2y^2}

Example Question #2 : Simplifying Radicals

\displaystyle Simplify \;\sqrt{396}

Possible Answers:

\displaystyle 6\sqrt{11}

\displaystyle 11\sqrt{2}

\displaystyle 17\sqrt{2}

\displaystyle 36\sqrt{11}

Correct answer:

\displaystyle 6\sqrt{11}

Explanation:
\(\displaystyle Factor\; 396\; under\; the\; radical\; sign\)\(\displaystyle \sqrt{396}\)  =  \(\displaystyle \sqrt{36\times 11}\)  =  \(\displaystyle \sqrt{6^{2}\times 11}\)

=\(\displaystyle \sqrt{6^2}\sqrt{11}\)
=\(\displaystyle 6\sqrt{11}\)

Example Question #1 : Factoring Radicals

Simplify the radical.

\displaystyle \small \sqrt{128}

Possible Answers:

\displaystyle \small 8\sqrt{132}

\displaystyle \small 8\sqrt2

Cannot be simplified further.

\displaystyle \small 4\sqrt{32}

\displaystyle \small 4\sqrt2

Correct answer:

\displaystyle \small 8\sqrt2

Explanation:

\displaystyle \small \sqrt{128}

Find the factors of 128 to simplify the term.

\displaystyle \small 64*2=128

We can rewrite the expression as the square roots of these factors.

\displaystyle \sqrt{128}=\sqrt{64}*\sqrt{2}

Simplify.

\displaystyle \sqrt{64}*\sqrt{2}=8\sqrt{2}

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