To solve the inequality \( 3(u - 10) + 18 \leq 12 \), we can follow these steps:
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Distribute and simplify the left side: \[ 3(u - 10) + 18 \leq 12 \] \[ 3u - 30 + 18 \leq 12 \] \[ 3u - 12 \leq 12 \]
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Add 12 to both sides: \[ 3u \leq 24 \]
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Divide by 3: \[ u \leq 8 \]
The solution set is \( u \leq 8 \).
Graphing the Solution:
- The solution \( u \leq 8 \) includes all numbers less than or equal to 8.
- We will represent this on a number line.
Steps to graph:
- Draw a number line.
- Plot the point at 8. Since the inequality is less than or equal to (≤), we use a closed dot at 8.
- Shade to the left of 8, indicating all values less than 8 are included in the solution.
Change from Closed to Open:
- If asked to change an endpoint from closed to open, we can modify it to \( u < 8 \) instead of \( u \leq 8 \) (this means moving from a closed dot to an open dot).
- Therefore, instead of shading up to and including 8, we would leave it out with an open dot.
Deleting the Middle of the Segment:
- You would keep all the shaded region to the left but ensure not to include the endpoint at 8, effectively marking it open.
Thus, the final graphical representation would have:
- An open dot at 8.
- Shading extending infinitely to the left towards negative infinity.
Final Answer:
- Solution: \( u \leq 8 \) (or \( u < 8 \) if changing to open).
- Graph: Closed dot at 8 (if original) or open dot at 8 (if changed), with shading to the left.