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Solve the inequality $4t^2 \le -9t + 12 - 14t + 36.$ Write your answer in interval notation.

 Jul 31, 2024
 #1
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First, let's move all the terms to one side and combine all like terms. 

We have the inequality

\(4t^2-48+23t\le \:0\)

 

Now, let's complete the square for t. We get

\(4\left(t+\frac{23}{8}\right)^2-\frac{1297}{16}\le \:0\)

 

This format allows us to isolate t in a much simpler manner. Now, let's start the process. We get

\(4\left(t+\frac{23}{8}\right)^2\le \:\frac{1297}{16}\)

\(\left(t+\frac{23}{8}\right)^2\le \:\frac{1297}{64}\)

 

Now, square rooting both sides, it gives us two parameters to focus on for t. We get

\(-\sqrt{\frac{1297}{64}}\le \:t+\frac{23}{8}\le \:\sqrt{\frac{1297}{64}}\\ \frac{-\sqrt{1297}-23}{8}\le \:t\le \:\frac{\sqrt{1297}-23}{8}\)

 

Now, the final step is to write this in interval notation. We finally get that t is \([\frac{-\sqrt{1297}-23}{8},\frac{\sqrt{1297}-23}{8}]\)

 

Thanks! :)

 Jul 31, 2024
edited by NotThatSmart  Jul 31, 2024

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