Math, asked by rehmath3161, 4 hours ago

5/√18-√7 rationalise by denominator

Answers

Answered by Anonymous
28

Step-by-step explanation:

We know that,

(a - b)(a + b) = a² - b²

 \large  \bold{ \frac{5}{ \sqrt{18} -  \sqrt{7}  }  }\\  \\    \large  \bold{= \frac{5}{( \sqrt{18}  -  \sqrt{7} )}  \times  \frac{( \sqrt{18} +  \sqrt{7})  }{( \sqrt{18} +  \sqrt{7}  )}  }\\ \\ \large  \bold{  =  \frac{5(\sqrt{18} +  \sqrt{7})}{ {( \sqrt{18} )}^{2} -  {( \sqrt{7} )}^{2}  } } \\  \\  \large  \bold{=  \frac{5( 3\sqrt{2}  +  \sqrt{7} )}{18 - 7}  }\\ \\  \large  \bold{ =  \red{ \frac{15 \sqrt{2}  + 5 \sqrt{7} }{11} }}

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