Question

Ifxy=-30 and x^2+y^2=61 then find the value of (X+y)

Answer 1

$- 30^{2} + - 30 ^{2} = 61 \\ - 900 - 900 = 61 \\ value \: o \: x + y \: \\ - 1800$ please mark as brainlist.

Answer 2

Answer:

±1

Given:

• xy = -30
• x² + y² = 61

Step-by-step explanation:

• Double 'xy = -30'

2xy = -60

• Add both 'xy = -30' and 'x² + y² = 61'.

x² + y² + 2xy = 61 - 60

x² + y² + 2xy = 1

• Factorise the LHS.

(x + y)² = 1

• Take the square root of both sides.

x + y = ± 1

• Thus the answer is +1 or -1.