1.

The sum of a number and its positive square root is 6/25. Find the number.

Answer»

Given: The sum of a number and its positive square root is 6/25. 

To find: the number.Solution:Let the number be ‘a’.

⇒ a + √a = 6/25 

⇒ √a = (6/25) – a 

Squaring both sides

⇒ a = 36/625 + a2 – 12a/25 

⇒ a2 – 37a/25 + 36/625 = 0

factorise by splitting the middle term. 

⇒ a2 – a/25 – 36a/25 + 36/625 = 0 

⇒ a(a – 1/25) – (36/25) × (a – 1/25) = 0 

⇒ (a – 36/25)(a – 1/25) = 0 

⇒ a = 36/25 , 1/25 

But only 1/25 is possible as its sum with its positive root is 6/25.

Hence the number is 1/25.



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