Q5 of 108 Page 42

Divide 16 into two parts such that two times the square of the larger part is 164 more than the square of the smaller part.

Let the smaller part be x and the larger part be 16 – x.

Given:


2 × (Larger Part)2 = (Smaller Part)2 + 164


2 × (16 – x)2 = (x)2 + 164


2 × (256 – 32x + x2) = x2 + 164


512 – 64x + 2 x2 = x2 + 164


x2 – 64x + 512 – 164 = 0


x2 – 64x + 348 = 0


On factorizing the above equation,


Sum = -64


Product = 348


Therefore the two numbers satisfying the above conditions are -58 and -6.


x2 – 6x - 58x + 348 = 0


x(x – 6) - 58(x – 6) = 0


(x – 6) (x - 58) = 0


Solving first part,


x – 6 = 0


a = 6


Solving second part,


x - 58 = 0


x = 58


Since x is the smaller it cannot be greater than 16. Hence x cannot be 58


So the smaller part is x = 6


So the larger Part = 16 – 6


= 10


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