Question

x-y = 9 and xy = 10, What is 1/x-1/y ?

• A. 9/10
• B. 10/9
• C. -9/10
• D. -10/9

Answer 1

Answer:

C. -9/10

$\frac{1}{x}-\frac{1}{y}=\frac{y-x}{xy}$

$=\frac{-9}{10}$