Question

9.  If x + y = 3, x 2  + y 2  = 5 then xy is

Answer 1

Answer:

(a+b)^2=a^2+^2+2ab

Here let a=x andb=y

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

3^2=5+2xy

9=5+2xy

9-5=2xy

4=2xy

4/2=xy

2=xy

Therefore xy=2