Question

(vi) If x −y = 11 and xy = 9 then x² +y ² is equal to (a) 112 (b) 139 (c) 103 (d) 130

Answer 1

★ Answer :

x - y = 11 .......(1)

xy = 9 ........(2)

Squaring both sides in equation (1).

→ (x - y)² = 11²

We know that,

(x - y)² = x² + y² - 2xy

→ x² + y² - 2xy = 121 ......(3)

From equation to put value of xy in equation (3).

→ x² + y² - 2(9) = 121

→ x² + y² - 18 = 121

→ x² + y² = 121 + 18

→ x² + y² = 139

So, Option B is correct.