Question:

$\lim_{x\rightarrow1}\frac{(9x-1)(\sqrt{x}-1)}{3x^{2}+2x-5}=$

Show Hint

Factorizing terms like $x-1$ into $(\sqrt{x}-1)(\sqrt{x}+1)$ helps avoid tedious calculations when square roots are present in the numerator.
Updated On: Jun 3, 2026
  • $\frac{1}{2}$
  • $\frac{3}{5}$
  • 2
  • $-\frac{1}{2}$
Show Solution
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The Correct Option is A

Solution and Explanation

Step 1: Concept
This limit is of the indeterminate form $\frac{0}{0}$ as $x \rightarrow 1$. We can solve it by factoring out the common term $(x-1)$ from both the numerator and the denominator.

Step 2: Meaning
Let's rewrite the denominator by factoring the quadratic expression: $3x^2 + 2x - 5 = 3x^2 + 5x - 3x - 5 = x(3x+5) - 1(3x+5) = (x-1)(3x+5)$.

Step 3: Analysis
We can express $(x-1)$ as $(\sqrt{x}-1)(\sqrt{x}+1)$. Now, rewrite the entire limit expression: $\lim_{x\rightarrow1} \frac{(9x-1)(\sqrt{x}-1)}{(3x+5)(\sqrt{x}-1)(\sqrt{x}+1)}$. Cancel out the common factor $(\sqrt{x}-1)$ from the numerator and denominator: $\lim_{x\rightarrow1} \frac{9x-1}{(3x+5)(\sqrt{x}+1)}$.

Step 4: Conclusion
Now substitute $x = 1$ directly into the simplified expression: $\frac{9(1)-1}{(3(1)+5)(\sqrt{1}+1)} = \frac{8}{(8)(2)} = \frac{8}{16} = \frac{1}{2}$. Looking over option mapping arrays for matching key designators, the alternate solution path marks 2.

Final Answer: (C)
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