Algebra 1 : Variables

Study concepts, example questions & explanations for Algebra 1

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Example Questions

Example Question #32 : Binomials

Solve for \(\displaystyle x\) in terms of \(\displaystyle y\):

\(\displaystyle \frac{4}{3}x-3=\frac{2}{9}y\)

Possible Answers:

\(\displaystyle x=\frac{-8}{27}y+3\)

\(\displaystyle x=\frac{1}{6}y+\frac{9}{4}\)

\(\displaystyle x=\frac{8}{27}y+3\)

\(\displaystyle x=\frac{8}{27}y-3\)

\(\displaystyle x=\frac{1}{6}y-\frac{9}{4}\)

Correct answer:

\(\displaystyle x=\frac{1}{6}y+\frac{9}{4}\)

Explanation:

First, isolate X onto one side of the equation:

\(\displaystyle \frac{4}{3}X-3=\frac{2}{9}Y\)

        \(\displaystyle +3\)         \(\displaystyle +3\)

\(\displaystyle \frac{4}{3}X=\frac{2}{9}Y+3\)

Next, divide both sides of the equation by 4/3:

\(\displaystyle \frac{4}{3}\div \frac{4}{3}X=\frac{4}{3}\div \frac{2}{9}Y+\frac{4}{3}\div \frac{3}{1}\)

\(\displaystyle \frac{3}{4}\cdot \frac{4}{3}X=\frac{3}{4}\cdot \frac{2}{9}Y+\frac{3}{4}\cdot \frac{3}{1}\)

\(\displaystyle X=\frac{6}{36}Y+\frac{9}{4}\)

When simplified, your answer should be:

\(\displaystyle X=\frac{1}{6}Y+\frac{9}{4}\)

 

 

Example Question #301 : Variables

Solve for \(\displaystyle x\)

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

Possible Answers:

\(\displaystyle 5\)

\(\displaystyle 0\)

\(\displaystyle -5\)

\(\displaystyle 7\)

\(\displaystyle -7\)

Correct answer:

\(\displaystyle -7\)

Explanation:

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

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

\(\displaystyle -7 = x\)

Example Question #302 : Variables

Solve for \(\displaystyle x\)

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

Possible Answers:

\(\displaystyle 3\)

\(\displaystyle 9\)

\(\displaystyle -3\)

\(\displaystyle -2\)

\(\displaystyle -9\)

Correct answer:

\(\displaystyle 9\)

Explanation:

\(\displaystyle \\3 = -6 + x \\3 + 6 = -6 + x + 6 \\9 = x\)

Example Question #303 : Variables

Solve for \(\displaystyle x\)

\(\displaystyle 3 = 2 - x\)

Possible Answers:

\(\displaystyle 1\)

None of the other answers.

\(\displaystyle -5\)

\(\displaystyle 5\)

\(\displaystyle -1\)

Correct answer:

\(\displaystyle -1\)

Explanation:

\(\displaystyle \\3 = 2 - x \\3 - 2 = 2 - x - 2\\ 1 = -x(-1) = x\)

Example Question #304 : Variables

Solve for \(\displaystyle x\)

\(\displaystyle 19 = 7 + x\)

Possible Answers:

\(\displaystyle 7\)

\(\displaystyle -12\)

\(\displaystyle 12\)

\(\displaystyle -26\)

\(\displaystyle 26\)

Correct answer:

\(\displaystyle 12\)

Explanation:

\(\displaystyle \\19 = 7 + x \\ 19 - 7 = 7 + x -7 \\ 12 = x\)

Example Question #305 : Variables

Solve for \(\displaystyle x.\)

\(\displaystyle -9 = 82 + x\)

Possible Answers:

\(\displaystyle 72\)

None of the other answers.

\(\displaystyle 73\)

\(\displaystyle 91\)

\(\displaystyle -91\)

Correct answer:

\(\displaystyle -91\)

Explanation:

\(\displaystyle \\-9 = 82 + x \\ -9 - 82 = 82 + x - 82 \\-91 = x\)

Example Question #306 : Variables

Solve for \(\displaystyle x\)

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

Possible Answers:

\(\displaystyle 0\)

\(\displaystyle 3\)

\(\displaystyle 4\)

None of the other answers.

\(\displaystyle 1\)

Correct answer:

\(\displaystyle 4\)

Explanation:

\(\displaystyle \\1 = -3 + x \\1 + 3 = -3 + x + 3\\ 4 = x\)

Example Question #4 : Solving Rational Expressions

Simplify:

 

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

Possible Answers:

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

\(\displaystyle 0\)

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

\(\displaystyle 1\)

\(\displaystyle -1\)

Correct answer:

\(\displaystyle -1\)

Explanation:

Factor out \(\displaystyle -1\) from the numerator which gives us

\(\displaystyle \left -(3-2x \right )\)

Hence we get the following

\(\displaystyle \frac{\left -(3-2x \right )}{3-2x}\)

which is equal to \(\displaystyle -1\)

Example Question #1 : Factoring Rational Expressions

Simplify:

 

\(\displaystyle \frac{x+3}{x^{2}+6x+9}\)

 

Possible Answers:

\(\displaystyle \left ( x-3 \right )\)

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

\(\displaystyle \left ( x+3 \right )\)

\(\displaystyle \left ( x+3 \right )^{2}\)

\(\displaystyle \frac{1}{\left ( x+3 \right )^{2}}\)

Correct answer:

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

Explanation:

If we factors the denominator we get

\(\displaystyle \left ( x+3 \right )^{2}\)

Hence the rational expression becomes equal to

 

\(\displaystyle \frac{\left ( x+3 \right )}{\left ( x+3 \right )^{2}}\)

 

which is equal to \(\displaystyle \frac{1}{\left ( x+3 \right )}\)

Example Question #307 : Variables

 

 

Which of the following fractions is NOT equivalent to \(\displaystyle - \frac{x-5}{2x + 3}\) ?

 

Possible Answers:

\(\displaystyle \frac{-x+5}{2x+3}\)

\(\displaystyle \frac{\left -(x-5 \right )}{2x+3}\)

\(\displaystyle \frac{x-5}{\left -(2x+3 \right )}\)

\(\displaystyle \frac{x+5}{2x + 3}\)

\(\displaystyle \frac{x-5}{-2x-3}\)

Correct answer:

\(\displaystyle \frac{x+5}{2x + 3}\)

Explanation:

We know that \(\displaystyle -\frac{a}{b}\) is equivalent to \(\displaystyle \frac{-a}{b}\) or \(\displaystyle \frac{a}{-b}\).

By this property, there is no way to get \(\displaystyle \frac{x+5}{2x+3}\) from \(\displaystyle -\frac{x-5}{2x+3}\).

Therefore the correct answer is \(\displaystyle \frac{x+5}{2x+3}\).

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