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If (log(3)x)^(2)+log(3)x lt2, then whic...

If `(log_(3)x)^(2)+log_(3)x lt2`, then which one of the following is correct?

A

`0 lt x lt 1/9`

B

` 1/9 le x le 3`

C

`3 lt x lt oo`

D

` 1/9 le x le 3`

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The correct Answer is:
To solve the inequality \((\log_{3} x)^{2} + \log_{3} x < 2\), we will follow these steps: ### Step 1: Substitute \(y\) for \(\log_{3} x\) Let \(y = \log_{3} x\). Then, the inequality becomes: \[ y^2 + y < 2 \] ### Step 2: Rearrange the inequality Rearranging gives us: \[ y^2 + y - 2 < 0 \] ### Step 3: Factor the quadratic expression We need to factor the quadratic expression \(y^2 + y - 2\). We look for two numbers that multiply to \(-2\) and add to \(1\). These numbers are \(2\) and \(-1\). Thus, we can factor it as: \[ (y + 2)(y - 1) < 0 \] ### Step 4: Determine the critical points The critical points from the factors are: \[ y + 2 = 0 \quad \Rightarrow \quad y = -2 \] \[ y - 1 = 0 \quad \Rightarrow \quad y = 1 \] ### Step 5: Test intervals We will test the intervals determined by the critical points \(-2\) and \(1\): - **Interval 1**: \(y < -2\) (e.g., \(y = -3\)) \(((-3) + 2)((-3) - 1) = (-1)(-4) > 0\) - **Interval 2**: \(-2 < y < 1\) (e.g., \(y = 0\)) \(((0) + 2)((0) - 1) = (2)(-1) < 0\) - **Interval 3**: \(y > 1\) (e.g., \(y = 2\)) \(((2) + 2)((2) - 1) = (4)(1) > 0\) ### Step 6: Write the solution in terms of \(y\) The inequality \((y + 2)(y - 1) < 0\) holds true in the interval: \[ -2 < y < 1 \] ### Step 7: Substitute back for \(x\) Now, substituting back for \(y\): \[ -2 < \log_{3} x < 1 \] ### Step 8: Convert the logarithmic inequalities to exponential form 1. From \(-2 < \log_{3} x\): \[ x > 3^{-2} = \frac{1}{9} \] 2. From \(\log_{3} x < 1\): \[ x < 3^{1} = 3 \] ### Final Solution Thus, the solution for \(x\) is: \[ \frac{1}{9} < x < 3 \]

To solve the inequality \((\log_{3} x)^{2} + \log_{3} x < 2\), we will follow these steps: ### Step 1: Substitute \(y\) for \(\log_{3} x\) Let \(y = \log_{3} x\). Then, the inequality becomes: \[ y^2 + y < 2 \] ...
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