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The sum of two numbers is 9 and the sum of their squares are 41. The numbers are:
Question

The sum of two numbers is 9 and the sum of their squares are 41. The numbers are:

A.

5, 4

B.

1, 8

C.

6, 3

D.

7, 2

Correct option is A

Given:

Sum of two numbers: x + y = 9

Sum of their squares: x2^2​ + y2^2​ = 41

Concept Used:

(x + y)2^2​ = x2^2​ + y2^2​ + 2xy

Solution: 

Now, 

2xy = (x + y)2^2​ - (x2^2​ + y2^2​)

2xy = 92^2​ - 41

2xy = 81 - 41 = 40

xy = 20

So, 

Sum of number = 9 

Product of numbers, xy = 20 

So, 

t2^2​ - 9t + 20 = 0

(t - 5)(t - 4) = 0

The numbers are 5 and 4.

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