Question

find the value of 'xy' ( using appropriate identity) if : X+y=3 and x²+y²=5
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Answer 1

Step-by-step explanation:

given, x + y = 3

x² + y² = 5

use the formula : (a + b)² = a² + b² + 2ab

(x + y)² = x² + y² + 2xy

3² = 5 + 2xy

9 - 5 = 2xy

4 = 2xy

xy = 4/2

2