Algebra II : Equations

Study concepts, example questions & explanations for Algebra II

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Example Questions

Example Question #61 : Solving Equations

Solve for x: \(\displaystyle bx-cx=x-2\)

Possible Answers:

Cannot be solved

\(\displaystyle x=\frac{b-c-1}{2}\)

\(\displaystyle x=\frac{-2}{b-c-1}\)

\(\displaystyle x=\frac{b-c-1}{-2}\)

\(\displaystyle x=\frac{-1}{b-c}\)

Correct answer:

\(\displaystyle x=\frac{-2}{b-c-1}\)

Explanation:

\(\displaystyle bx-cx=x-2\)

Subtract to move all x terms to the same side:

\(\displaystyle bx-cx-x=-2\)

Factor out an x:

\(\displaystyle x(b-c-1)=-2\)

Divide to isolate x completely:

\(\displaystyle \mathbf{x=\frac{-2}{b-c-1}}\)

Example Question #551 : Basic Single Variable Algebra

Solve for x: \(\displaystyle \sqrt{2x-4x}=\sqrt{x-2}\)

Possible Answers:

\(\displaystyle x=-2\)

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

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

\(\displaystyle x=2\)

\(\displaystyle x=1\)

Correct answer:

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

Explanation:

\(\displaystyle \sqrt{2x-4x}=\sqrt{x-2}\)

Square both sides to remove the radicals:

\(\displaystyle 2x-4x=x-2\)

Combine x terms:

\(\displaystyle -2x=x-2\)

Combine x terms to one side by subtracting:

\(\displaystyle -3x=-2\)

Isolate x completely:

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

 

 

Example Question #72 : Solving Equations

Find the solution to the following equation.

\(\displaystyle 9x+23=59\)

Possible Answers:

\(\displaystyle x=4\)

\(\displaystyle x=36\)

\(\displaystyle x=40.5\)

\(\displaystyle x=-4\)

Correct answer:

\(\displaystyle x=4\)

Explanation:

Find the solution to the following equation.

\(\displaystyle 9x+23=59\)

To find the solution of this equation, we need to find the value for x, which makes the given equation true.

We do this by working backwards and manipulating the equation.

The easiest first step would probably be to subtract 23 from both sides:

\(\displaystyle 9x+23(-23)=59(-23)\)

By doing so, we can simplify the equation to get:

\(\displaystyle 9x=36\)

Next, simply divide both sides by 9 to get the answer!

\(\displaystyle 9x\div 9=36\div9\)

So we get:

\(\displaystyle x=4\)

Example Question #2391 : Algebra Ii

Given the following equation, find the value of  \(\displaystyle b^3\) 

\(\displaystyle 355=7b+12\)

Possible Answers:

\(\displaystyle 343\)

\(\displaystyle 117649\)

\(\displaystyle 49\)

\(\displaystyle 77\)

Correct answer:

\(\displaystyle 117649\)

Explanation:

Given the following equation, find the value of  \(\displaystyle b^3\) 

\(\displaystyle 355=7b+12\)

To find the value of \(\displaystyle b^3\), we first need to find the value of b

Let's begin by subtracting 12

\(\displaystyle 355(-12)=7b+12(-12)\)

Simplify

\(\displaystyle 343=7b\)

Finally, divide by 7

\(\displaystyle b=\frac{343}{7}=49\)

But, we need \(\displaystyle b^3\)

So:

\(\displaystyle b^3=49^3=117649\)

 

Example Question #201 : Equations

\(\displaystyle 27x-9=-18\)

Possible Answers:

\(\displaystyle x=-\frac{1}{3}\)

None of these

\(\displaystyle x=\frac{1}{3}\)

\(\displaystyle x=-3\)

\(\displaystyle x=3\)

Correct answer:

\(\displaystyle x=-\frac{1}{3}\)

Explanation:

\(\displaystyle 27x-9=-18\)

Add 9 to both sides:

\(\displaystyle 27x=-9\)

Divide both sides by 27:

\(\displaystyle \mathbf{x=-\frac{1}{3}}\)

Example Question #201 : Equations

\(\displaystyle 27x-9=-18\)

Possible Answers:

\(\displaystyle x=-\frac{1}{3}\)

None of these

\(\displaystyle x=\frac{1}{3}\)

\(\displaystyle x=-3\)

\(\displaystyle x=3\)

Correct answer:

\(\displaystyle x=-\frac{1}{3}\)

Explanation:

\(\displaystyle 27x-9=-18\)

Add 9 to both sides:

\(\displaystyle 27x=-9\)

Divide both sides by 27:

\(\displaystyle \mathbf{x=-\frac{1}{3}}\)

Example Question #73 : Solving Equations

I sell bagels for \(\displaystyle 25\) cents plus ten cents for the bag it comes in. How many bagels can u buy if you brought $\(\displaystyle 3.35\)?

Possible Answers:

\(\displaystyle 15\)

\(\displaystyle 13\)

\(\displaystyle 12\)

\(\displaystyle 14\)

\(\displaystyle 11\)

Correct answer:

\(\displaystyle 13\)

Explanation:

Let's set-up an equation. 

\(\displaystyle .25x+.10=3.35\) \(\displaystyle x\) represents the amount of bagels. After subtracting \(\displaystyle .10\) on both sides and dividing by \(\displaystyle 0.25\), our answer should be \(\displaystyle 13\) bagels.

Example Question #2393 : Algebra Ii

Bob rides in a NYC taxi in which the opening fare is $\(\displaystyle 2.00\). The taxi charges \(\displaystyle 30\)cents for every \(\displaystyle \frac{1}{5}\) of a mile. How far did Bob go if the fare costs $\(\displaystyle 21.80\)?

Possible Answers:

\(\displaystyle 44\)

\(\displaystyle 66\)

\(\displaystyle 14.6\)

\(\displaystyle 13.2\)

\(\displaystyle 12.8\)

Correct answer:

\(\displaystyle 13.2\)

Explanation:

Let's set-up an equation. 

\(\displaystyle 2+0.3x=21.80\) \(\displaystyle x\) how many fifth miles the taxi charges. After subtracting \(\displaystyle 2\) on both sides and dividing by \(\displaystyle 0.3\), our answer should be \(\displaystyle 66\). But of course, this is not the final answer because that's how many times the taxi charges for every fifth mile. So \(\displaystyle 66*\frac{1}{5}=13.2\) miles.

Example Question #71 : Solving Equations

A gas tank holds \(\displaystyle 20\) gallons. A car uses \(\displaystyle \frac{1}{40}\) of a gallon per mile. How many gallons is left if the person travelled \(\displaystyle 600\) miles?

Possible Answers:

\(\displaystyle 2\)

\(\displaystyle 4\)

\(\displaystyle 6\)

\(\displaystyle 3\)

\(\displaystyle 5\)

Correct answer:

\(\displaystyle 5\)

Explanation:

Since the person has traveled  \(\displaystyle 600\) miles and each mile uses \(\displaystyle \frac{1}{40}\) gallon, we can determine how many gallons used.  \(\displaystyle \frac{600}{40}=15\) gallons used. Since a tank holds \(\displaystyle 20\) gallons, we subtract \(\displaystyle 20\) and \(\displaystyle 15\) to get \(\displaystyle 5\) gallons. 

Example Question #211 : Equations

Josh weighs \(\displaystyle 300\) pounds. He goes on a diet and loses \(\displaystyle 2\) pounds every \(\displaystyle 5\) days. How long does it take for him to drop to \(\displaystyle 180\) pounds?

Possible Answers:

\(\displaystyle 60\)

\(\displaystyle 120\)

\(\displaystyle 300\)

\(\displaystyle 50\)

\(\displaystyle 360\)

Correct answer:

\(\displaystyle 300\)

Explanation:

Let's set-up an equation.

\(\displaystyle 300-2x=180\) \(\displaystyle x\) represents how many times he lost the \(\displaystyle 2\) pounds. By subtracting \(\displaystyle 300\) on both sides and dividing by \(\displaystyle -2\) later, we get \(\displaystyle 60\). That's not our answer as he loses weight every five days. So we do \(\displaystyle 60*5=300\) days. 

 

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