Question

x + y = 3, x² + y2 = 12, 2xy =​

Answer 1

Answer:

Given

$x + y = 3$

${x}^{2} + {y}^{2} = 12 \\ ( {x + y)}^{2} - 2xy = 12 \\ {3 }^{2} - 2xy = 12 \\ 2xy = 9 - 12 \\ 2xy = - 3$

Answer 2

Answer: -3

Step-by-step explanation: in the equation a^2 +b^2=(a+b)^2-2ab

So here it is given that x+y=3 and x^2+y^2=12 so by applying the formula above :

x^2+y^2=(x+y)^2-2xy

=>12=(3^2)-2xy

=>12=9-2xy

=>12-9=-2xy

=>-2xy=3

=>2xy=-3