Question

If x + y = 15 and xy = 14, then the value of x – y is :

• A. 12
• B. 14
• C. 13
• D. 11

Answer 1

Answer:

C. 13

Given:

x + y = 15, xy = 14

Formula Used:

(x – y)² = (x + y)² – 4xy

Calculation:

⇒ (x – y)² = (15)² – $4\times{14}$ = 225 – 56 = 169

∴ x – y = 13