College Algebra : Review and Other Topics

Study concepts, example questions & explanations for College Algebra

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Example Questions

Example Question #1 : Simplifying Exponents

Simplify the expression:

\(\displaystyle (3x^4y^2)(4xy^2)^{-3}\)

Possible Answers:

\(\displaystyle 3xy\)

Cannot be simplified

\(\displaystyle \frac{3x}{64y^4}\)

\(\displaystyle \frac{3x}{64y^3}\)

\(\displaystyle \frac{3x}{16y^3}\)

Correct answer:

\(\displaystyle \frac{3x}{64y^4}\)

Explanation:

Begin by distributing the exponent through the parentheses. The power rule dictates that an exponent raised to another exponent means that the two exponents are multiplied:

\(\displaystyle (3x^{4}y^2)(4xy^2)^{-3}= (3xy^2)(4^{-3}x^{-3}y^{-6})\)

Any negative exponents can be converted to positive exponents in the denominator of a fraction:

\(\displaystyle \frac{3x^4y^2}{64x^3y^6}\)

The like terms can be simplified by subtracting the power of the denominator from the power of the numerator:

\(\displaystyle \frac{3x^4y^2}{64x^3y^6}=\frac{3}{64}x^{4-3}y^{2-6}=\frac{3}{64}xy^{-4}\)

\(\displaystyle \frac{3x}{64y^4}\)

Example Question #1 : Expressions & Equations

Simplify:

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

Possible Answers:

\(\displaystyle 16x^7\)

\(\displaystyle 512x\)

\(\displaystyle 256x^{12}\)

\(\displaystyle 4x^7\)

\(\displaystyle 4x^{12}\)

Correct answer:

\(\displaystyle 256x^{12}\)

Explanation:

Use the power rule to distribute the exponent:

\(\displaystyle (4x^3)^4\rightarrow 4^4\cdot x^{3\cdot 4}\rightarrow 256x^{12}\)

Example Question #1 : Integer Exponents

Simplify the following expression:

\(\displaystyle (9x^6y^2z^5)^2\)

Possible Answers:

\(\displaystyle 81x^{12}y^4z^{10}\)

\(\displaystyle 11x^{12}y^4z^{10}\)

\(\displaystyle 81x^{8}y^4z^{7}\)

\(\displaystyle 18x^{12}y^4z^{10}\)

Correct answer:

\(\displaystyle 81x^{12}y^4z^{10}\)

Explanation:

Simplify the following expression:

\(\displaystyle (9x^6y^2z^5)^2\)

To raise exponents to another power, we need to multiply them:

\(\displaystyle (9x^6y^2z^5)^2=9^2x^{6*2}y^{2*2}z^{5*2}=81x^{12}y^4z^{10}\)

So we get:

\(\displaystyle 81x^{12}y^4z^{10}\)

 

Example Question #2 : Integer Exponents

Simplify.

\(\displaystyle (x^4)^{6}\)

Possible Answers:

\(\displaystyle x^{46}\)

\(\displaystyle x^{24}\)

\(\displaystyle x^{-2}\)

\(\displaystyle x^{10}\)

\(\displaystyle x^2\)

Correct answer:

\(\displaystyle x^{24}\)

Explanation:

When an exponent is being raised by another exponent, we just multiply the powers of the exponents and keep the base the same.

\(\displaystyle (x^4)^{6}=x^{4*6}=x^{24}\)

Example Question #21 : Distributing Exponents (Power Rule)

Simplify.

\(\displaystyle (\frac{x^5}{y^3})^3\)

Possible Answers:

\(\displaystyle \frac{x^{8}}{y^6}\)

\(\displaystyle \frac{x^{15}}{y^8}\)

\(\displaystyle \frac{x^{15}}{y^{13}}\)

\(\displaystyle \frac{x^{15}}{y^9}\)

\(\displaystyle \frac{x^{15}}{y^3}\)

Correct answer:

\(\displaystyle \frac{x^{15}}{y^9}\)

Explanation:

When an exponent is being raised by another exponent, we just multiply the powers of the exponents and keep the base the same.

\(\displaystyle (\frac{x^5}{y^3})^{3}=\frac{x^{5*3}}{y^{3*3}}=\frac{x^{15}}{y^{9}}\)

Example Question #4 : Review And Other Topics

Combine the following terms:

\(\displaystyle 5x^4*3t^3*8x^3\)

Possible Answers:

\(\displaystyle 120x^7t^3\)

\(\displaystyle 120x^{36}\)

\(\displaystyle 16x^7t^3\)

\(\displaystyle 120x^{10}\)

Correct answer:

\(\displaystyle 120x^7t^3\)

Explanation:

Combine the following terms:

\(\displaystyle 5x^4*3t^3*8x^3\)

We need to multiply three terms together. We should recognize that the t must be left alone, because it cannot be combined with the x's. 

First, multiply all three coefficients

\(\displaystyle 5*3*8=120\)

Next, combine the x's. Because we are multiplying, we will add the exponents.

\(\displaystyle x^4*x^3=x^7\)

Now, put it all together to  get:

\(\displaystyle 120x^7t^3\)

Example Question #2 : Integer Exponents

Evaluate

\(\displaystyle X^7/X^4\)

Possible Answers:

\(\displaystyle X^{28}\)

\(\displaystyle X^{7/4}\)

\(\displaystyle X^{-3}\)

\(\displaystyle 7/4X\)

\(\displaystyle X^3\)

Correct answer:

\(\displaystyle X^3\)

Explanation:

When common variables with exponents are divided, the exponents are subtracted.

\(\displaystyle X^7/X^4 = X^{7-4} = X^3\)

Example Question #3 : Integer Exponents

Evaluate

\(\displaystyle X^8*X^6\)

Possible Answers:

\(\displaystyle X^{48}\)

\(\displaystyle 14X\)

\(\displaystyle X^{14}\)

\(\displaystyle 48X\)

\(\displaystyle X^{2}\)

Correct answer:

\(\displaystyle X^{14}\)

Explanation:

When like terms with exponents are multiplied, you add the exponents.

 

\(\displaystyle X^8*X^6 = X^{8+6} = X^{14}\)

Example Question #4 : Integer Exponents

Evaluate the following:

\(\displaystyle x^{2}*x^{4}=\)

Possible Answers:

\(\displaystyle 2x^{4}\)

\(\displaystyle 4x\)

\(\displaystyle x^{2}\)

\(\displaystyle x^{8}\)

\(\displaystyle x^{6}\)

Correct answer:

\(\displaystyle x^{6}\)

Explanation:

When similar terms raised to n are multiplied, simply add the exponents. Thus

\(\displaystyle x^{2}*x^{4}=x^{2+4}=x^{6}\)

Example Question #5 : Integer Exponents

\(\displaystyle x^{3}*x^{5}=\)

Possible Answers:

\(\displaystyle x^{2}\)

\(\displaystyle x^{5}\)

\(\displaystyle x^{15}\)

\(\displaystyle 15x\)

\(\displaystyle x^{8}\)

Correct answer:

\(\displaystyle x^{8}\)

Explanation:

When similar terms raised to n are multiplied, simply add the exponents. Thus

\(\displaystyle x^{3}*x^{5}=x^{3+5}=x^{8}\)

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