Question

what denominator do we obtain after rationalizing the denominator of 4÷7√5-5√7

Answer 1

Answer:

(7√5-5√7)(7√5+5√7)

= (7√5)²-(5√7)²   { as (a+b)(a-b)=a²-b² }

= (49×5)-(25×7)

= 245-175

= 70

And after cancelling 4 with 70

The final answer we get is 35

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