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# One-Step Equations Transformed by Multiplication/Division

## Multiplication or division to solve an equation.

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Practice One-Step Equations Transformed by Multiplication/Division
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Estimated10 minsto complete
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One-Step Equations Transformed by Multiplication-Division

What if you had an algebraic equation involving multiplication or division like \begin{align*}-5x = 3\end{align*}? How could you solve it for the unknown variable x? After completing this Concept, you'll be able to solve equations like this one.

### Watch This

CK-12 Foundation: 0302S Solving Equations with Multiplication and Division (H264)

### Guidance

#### Example C

Solve \begin{align*}5x = 3.25\end{align*}.

To cancel the 5, we divide both sides by 5.

#### Example D

Solve \begin{align*}1.375x = 1.2\end{align*}.

Divide by 1.375

Notice the bar above the final two decimals; it means that those digits recur, or repeat. The full answer is 0.872727272727272....

To see more examples of one - and two-step equation solving, watch the Khan Academy video series starting at http://www.youtube.com/watch?v=bAerID24QJ0.

Watch this video for help with the Examples above.

CK-12 Foundation: Solving Equations with Multiplication and Division

### Guided Practice

Solve:

a) \begin{align*} \frac{9x}{5} = 5\end{align*}.

b) \begin{align*}7x = \frac{5}{11}\end{align*}.

Solutions:

a) \begin{align*}\frac{9x}{5}\end{align*} is equivalent to \begin{align*} \frac{9}{5} \cdot x\end{align*}, so to cancel out that \begin{align*} \frac{9}{5}\end{align*}, we multiply by the reciprocal, \begin{align*} \frac{5}{9}\end{align*}.

b) Divide both sides by 7.

### Explore More

For 1-5, solve the following equations for \begin{align*}x\end{align*}.

1. \begin{align*}7x = 21 \end{align*}
2. \begin{align*}4x = 1 \end{align*}
3. \begin{align*}\frac{5x}{12} = \frac{2}{3}\end{align*}
4. \begin{align*}0.01x = 11\end{align*}
5. \begin{align*}\frac{-2x}{9} = \frac{10}{3}\end{align*}

For 6-10, solve the following equations for the unknown variable.

1. \begin{align*}21s = 3 \end{align*}
2. \begin{align*}-7a = -5 \end{align*}
3. \begin{align*}\frac{7f}{11} = \frac{7}{11} \end{align*}
4. \begin{align*}6r = \frac{3}{8} \end{align*}
5. \begin{align*}\frac{9b}{16} = \frac{3}{8} \end{align*}

### Answers for Explore More Problems

To view the Explore More answers, open this PDF file and look for section 3.2.