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Find 
lim_(x rarr1)(sqrt(5x+4)-3)/(x-1).
Choose 1 answer:
(A) 
(3)/(5)
(B) 
(5)/(6)
(c) 1
(D) The limit doesn't exist

Find limx15x+43x1 \lim _{x \rightarrow 1} \frac{\sqrt{5 x+4}-3}{x-1} .\newlineChoose 11 answer:\newline(A) 35 \frac{3}{5} \newline(B) 56 \frac{5}{6} \newline(C) 11\newline(D) The limit doesn't exist

Full solution

Q. Find limx15x+43x1 \lim _{x \rightarrow 1} \frac{\sqrt{5 x+4}-3}{x-1} .\newlineChoose 11 answer:\newline(A) 35 \frac{3}{5} \newline(B) 56 \frac{5}{6} \newline(C) 11\newline(D) The limit doesn't exist
  1. Evaluate Limit Directly: First, we need to evaluate the limit directly by substituting x=1x = 1 into the expression 5x+43x1\frac{\sqrt{5x+4}-3}{x-1} to see if it results in an indeterminate form.\newline\lim_{x \to 1}\frac{\sqrt{5x+4}-3}{x-1} = \frac{\sqrt{5(1)+4}-3}{1-1}\(\newline= \frac{\sqrt{9}-3}{0}\newline= \frac{3-3}{0}\newline= \frac{0}{0}\)\newlineThis is an indeterminate form, so we cannot evaluate the limit by direct substitution.
  2. Resolve Indeterminate Form: To resolve the indeterminate form, we can use algebraic manipulation. Specifically, we can multiply the numerator and the denominator by the conjugate of the numerator to eliminate the square root.\newlineThe conjugate of the numerator 5x+43\sqrt{5x+4}-3 is 5x+4+3\sqrt{5x+4}+3.\newlineWe multiply the original expression by (5x+4+3)/(5x+4+3)\left(\sqrt{5x+4}+3\right)/\left(\sqrt{5x+4}+3\right).\newlinelimx1(5x+43x1)(5x+4+35x+4+3)\lim_{x \to 1}\left(\frac{\sqrt{5x+4}-3}{x-1}\right) \cdot \left(\frac{\sqrt{5x+4}+3}{\sqrt{5x+4}+3}\right)
  3. Simplify Using Conjugate: Now, we simplify the expression by multiplying out the numerators and denominators.\newlinelimx1(5x+435x+4+3)(5x+4+3x1)\lim_{x \to 1}\left(\frac{\sqrt{5x+4}-3}{\sqrt{5x+4}+3}\right)\left(\frac{\sqrt{5x+4}+3}{x-1}\right)\newline= limx1((5x+4)9(x1)(5x+4+3))\lim_{x \to 1}\left(\frac{(5x+4) - 9}{(x-1)(\sqrt{5x+4}+3)}\right)\newline= limx1(5x5(x1)(5x+4+3))\lim_{x \to 1}\left(\frac{5x - 5}{(x-1)(\sqrt{5x+4}+3)}\right)
  4. Factor Out Numerator: We can now simplify the expression further by factoring out a 55 from the numerator.limx15(x1)(x1)(5x+4+3)\lim_{x \to 1}\frac{5(x - 1)}{(x-1)(\sqrt{5x+4}+3)}
  5. Cancel Common Factor: Since (x1)(x - 1) is a common factor in the numerator and the denominator, we can cancel it out.\newlinelimx15(5x+4+3)\lim_{x \to 1}\frac{5}{(\sqrt{5x+4}+3)}
  6. Evaluate Simplified Expression: Now we can evaluate the limit by substituting x=1x = 1 into the simplified expression.limx15(5(1)+4+3)\lim_{x \to 1}\frac{5}{(\sqrt{5(1)+4}+3)}= 5(9+3)\frac{5}{(\sqrt{9}+3)}= 53+3\frac{5}{3+3}= 56\frac{5}{6}
  7. Final Answer: The final answer is (B) (56)(\frac{5}{6}), which is the limit of the given expression as xx approaches 11.

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