A point \( P \) moves so that the sum of squares of its distances from the points \( (1, 2) \) and \( (-2, 1) \) is \( 14 \). Let \( f(x,y)=0 \) be the locus of \( P \), which intersects the x-axis at the points \( A, B \) and the y-axis at the points \( C, D \). Then the area of the quadrilateral \( ACBD \) is equal to:
