Answer:
xy = 16
Step-by-step explanation:
[tex]\frac{1}{x}[/tex] + [tex]\frac{1}{y}[/tex] = [tex]\frac{1}{2}[/tex] ( multiply through by 2xy to clear the fractions )
2y + 2x = xy ← factor out 2 from each term on the left side
2(y + x) = xy
substitute x + y = 8 into the left side
2(8) = xy , that is
xy = 16