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Solve the following absolute value equation 5|x+1|=10x=_x=_enter the negative solution first

Solve the following absolute value equation 5|x+1|=10x=_x=_enter the negative solution-example-1
User Kazeem
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1 Answer

20 votes
20 votes

Solution

- The question gives us the following expression to solve


5|x+1|=10

- Before we proceed, we should get rid of the 5 multiplying the absolute value function. This would enable us to work directly with the absolute value function and make our work a lot easier.

- To get rid of the 5, we can simply divide both sides by 5. This is done below:


\begin{gathered} 5|x+1|=10 \\ \text{ Divide both sides by 5} \\ \\ (5|x+1|)/(5)=(10)/(5) \\ \\ |x+1|=2 \end{gathered}

- Now, we can work directly with the absolute value function.

- The absolute value function has the property that


\begin{gathered} |x|=|-x|=x \\ \text{ That is, all negative numbers are made positive and positive numbers remain positive} \end{gathered}

- We can apply this rule to the question. Based on what we have discussed so far, we can conclude that the number or expression (x + 1) inside the absolute value function can either be positive or negative and they would still give us a positive 2 as a result.

- Thus, we can say:


\begin{gathered} x+1=2 \\ \text{ OR} \\ x+1=-2 \\ \\ \text{ To be sure that these are the two possibilities, we can take the absolute value of both sides for the two} \\ \text{ expressionis} \\ That\text{ is,} \\ \\ |x+1|=|2|=2 \\ OR \\ |x+1|=|-2|=2 \end{gathered}

- We can see that both expressions give us back the question. This means we just need to solve the two expressions and find the two possible values of x.

- This is done below:


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User Luke Quinane
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