SAT Math : Arithmetic

Study concepts, example questions & explanations for SAT Math

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Example Questions

Example Question #4 : How To Multiply Square Roots

Simplify:

\displaystyle (\sqrt{3}+\sqrt{5})(\sqrt{2}+\sqrt{6})

Possible Answers:

\displaystyle 4\sqrt{6}+5\sqrt{2}+\sqrt{3}

\displaystyle \sqrt{6}+\sqrt{30}

\displaystyle \sqrt{18}+\sqrt{10}

\displaystyle \sqrt{6}+3\sqrt{2}+\sqrt{10}+\sqrt{30}

\displaystyle \sqrt{6}+\sqrt{18}+\sqrt{10}+\sqrt{30}+8

Correct answer:

\displaystyle \sqrt{6}+3\sqrt{2}+\sqrt{10}+\sqrt{30}

Explanation:

To simplify the problem, just distribute the radical to each term in the parentheses. 

\displaystyle (\sqrt{3}+\sqrt{5})(\sqrt{2}+\sqrt{6})=

\displaystyle \sqrt{6}+\sqrt{18}+\sqrt{10}+\sqrt{30}=

\displaystyle \sqrt{6}+3\sqrt{2}+\sqrt{10}+\sqrt{30}

Example Question #2 : How To Multiply Square Roots

Evaluate and simplify: 

\displaystyle \sqrt{10}*\sqrt{12}

Possible Answers:

\displaystyle 2\sqrt{30}

\displaystyle 4\sqrt{5}

\displaystyle \sqrt{22}

\displaystyle 30\sqrt{2}

\displaystyle 20\sqrt{6}

Correct answer:

\displaystyle 2\sqrt{30}

Explanation:

To multiply square roots, we multiply the numbers inside the radical and we can simplify them if possible.

\displaystyle \\ \sqrt{10}*\sqrt{12}\\=\sqrt{10*12}\\=\sqrt{120}\\=\sqrt{4}*\sqrt{30}\\=2\sqrt{30}

Example Question #1 : How To Multiply Square Roots

Simplify and evaluate: 

\displaystyle \sqrt{12}*\sqrt{48}

Possible Answers:

\displaystyle 24\sqrt{3}

\displaystyle 18

\displaystyle 24

\displaystyle 16\sqrt{2}

\displaystyle 8\sqrt{3}

Correct answer:

\displaystyle 24

Explanation:

To multiply square roots, we multiply the numbers inside the radical and we can simplify them if possible.

In this case, let's simplify each individual radical and multiply them.

\displaystyle \\\sqrt{12}*\sqrt{48}\\=\sqrt{4}*\sqrt{3}*\sqrt{16}*\sqrt{3}\\=2\sqrt{3}*4\sqrt{3}\\=8*3=24

 

Example Question #6 : How To Multiply Square Roots

Simplify: \displaystyle \sqrt{x+5}*\sqrt{x-5}

Possible Answers:

\displaystyle x+5

\displaystyle x-5

\displaystyle \sqrt{x^2-25}

\displaystyle x^2-25

\displaystyle \sqrt{x^2-10}

Correct answer:

\displaystyle \sqrt{x^2-25}

Explanation:

To multiply square roots, we multiply the numbers inside the radical and we can simplify them if possible.

\displaystyle \\\sqrt{x+5}*\sqrt{x-5}\\=\sqrt{(x+5)(x-5)}\\=\sqrt{x^2-25}

Example Question #7 : How To Multiply Square Roots

Simplify: 

\displaystyle \sqrt{6}*2\sqrt{3}

Possible Answers:

\displaystyle 4\sqrt{6}

\displaystyle 12\sqrt{2}

\displaystyle 2\sqrt{6}

\displaystyle 6\sqrt{3}

\displaystyle 6\sqrt{2}

Correct answer:

\displaystyle 6\sqrt{2}

Explanation:

To multiply square roots, we multiply the numbers inside the radical.

Any numbers outside the radical are also multiplied. We can simplify them if possible.

\displaystyle \\\sqrt{6}*2\sqrt{3}\\=2\sqrt{6*3}\\=2\sqrt{18}\\=2\sqrt{9}*\sqrt{2}\\=2*3\sqrt{2}\\=6\sqrt{2}

Example Question #2 : How To Multiply Square Roots

Simplify: 

\displaystyle 4\sqrt{7}*\sqrt{21}

Possible Answers:

\displaystyle 7\sqrt{7}

\displaystyle 3\sqrt{7}

\displaystyle 12\sqrt{21}

\displaystyle 11\sqrt{3}

\displaystyle 28\sqrt{3}

Correct answer:

\displaystyle 28\sqrt{3}

Explanation:

To multiply square roots, we multiply the numbers inside the radical.

Any numbers outside the radical are also multiplied. 

We can simplify them if possible.

\displaystyle \\4\sqrt{7}*\sqrt{21}\\ =4\sqrt{7*21}\\=4\sqrt{7*7*3}\\=4*7\sqrt{3}\\=28\sqrt{3}

Example Question #1 : How To Multiply Square Roots

Simplify: 

\displaystyle 2\sqrt{10}*5\sqrt{20}

Possible Answers:

\displaystyle 50\sqrt{2}

\displaystyle 40\sqrt{10}

\displaystyle 200

\displaystyle 20\sqrt{5}

\displaystyle 100\sqrt{2}

Correct answer:

\displaystyle 100\sqrt{2}

Explanation:

To multiply square roots, we multiply the numbers inside the radical.

Any numbers outside the radical are also multiplied. 

We can simplify them if possible.

\displaystyle \\2\sqrt{10}*5\sqrt{20}\\=10\sqrt{10*20}\\=10\sqrt{10*10*2}\\=10*10\sqrt{2}\\=100\sqrt{2}

Example Question #81 : Arithmetic

Simplify: 

\displaystyle \sqrt{3}(\sqrt{3}+4)

Possible Answers:

\displaystyle 12

\displaystyle 7\sqrt{3}

\displaystyle 3+2\sqrt{3}

\displaystyle 3+4\sqrt{3}

\displaystyle 9+4\sqrt{3}

Correct answer:

\displaystyle 3+4\sqrt{3}

Explanation:

To simplify the problem, just distribute the radical to each term in the parentheses. 

\displaystyle \\\sqrt{3}(\sqrt{3}+4)\\=\sqrt{9}+4\sqrt{3}\\=3+4\sqrt{3}

Example Question #82 : Arithmetic

Simplify: 

\displaystyle \sqrt{3}(\sqrt{7}+\sqrt{12})

Possible Answers:

\displaystyle 12+4\sqrt{3}

\displaystyle \sqrt{21}+3\sqrt{3}

\displaystyle 21+3\sqrt{3}

\displaystyle \sqrt{21}+2\sqrt{2}

\displaystyle \sqrt{21}+6

Correct answer:

\displaystyle \sqrt{21}+6

Explanation:

To simplify the problem, just distribute the radical to each term in the parentheses. 

\displaystyle \\\sqrt{3}(\sqrt{7}+\sqrt{12})\\=\sqrt{21}+\sqrt{36}\\=\sqrt{21}+6

Example Question #83 : Arithmetic

Simplify: 

\displaystyle -\sqrt{6}(\sqrt{5}-\sqrt{2})

Possible Answers:

\displaystyle -\sqrt{30}-2\sqrt{3}

\displaystyle 2\sqrt{3}-\sqrt{30}

\displaystyle 12-\sqrt{30}

\displaystyle 2\sqrt{3}+\sqrt{30}

\displaystyle 3\sqrt{2}-\sqrt{30}

Correct answer:

\displaystyle 2\sqrt{3}-\sqrt{30}

Explanation:

To simplify the problem, just distribute the radical to each term in the parentheses. 

\displaystyle \\-\sqrt{6}(\sqrt{5}-\sqrt{2})\\=-\sqrt{30}+\sqrt{12}\\=-\sqrt{30}+2\sqrt{3}

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