<s>[INST] Need help conjugating I need some help conjugating because I feel like I am overlooking a step:
$$\lim_{x \rightarrow 4} \frac{3(x-4)(\sqrt{x+5})}{3 - \sqrt{x+5}}$$
I've done the conjugation by multiplying by $(3 + \sqrt{x+5})$ to clear out the bottom, but how would the top look like once multiplied?
 [/INST] $$\lim _{ x\rightarrow 4 } \frac { 3(x-4)(\sqrt { x+5 } ) }{ 3-\sqrt { x+5 }  } =\lim _{ x\rightarrow 4 } \frac { 3(x-4)(\sqrt { x+5 } )\left( 3+\sqrt { x+5 }  \right)  }{ \left( 3-\sqrt { x+5 }  \right) \left( 3+\sqrt { x+5 }  \right)  } =\\ =\lim _{ x\rightarrow 4 } \frac { 3(x-4)(\sqrt { x+5 } )\left( 3+\sqrt { x+5 }  \right)  }{ 4-x } =-54$$
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