Question

Evaluate
$\rm \displaystyle \lim_{n\to 5}\ \frac{2x^{2}+9x-5}{x+5}$

Answer 1

Solution :

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i ) 2x²+9x-5

Splitting the middle term, we get

= 2x² + 10x -1x -5

= 2x(x+5) -1( x + 5 )

= (x+5)(2x-1) ----( 1 )

ii ) (2x²+9x-5)/(x+5)

= [(x+5)(2x-1)]/(x+5) { from ( 1 ) }

= 2x -1 -----( 2 )
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$\rm \displaystyle \lim_{x\to 5}\ \frac{2x^{2}+9x-5}{x+5}$

= $\rm \displaystyle \lim_{x\to 5}\ \textsf{ 2x - 1 }$

= 2×5 - 1

= 10 -1

= 9

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