Question

if 4 x^2 +9 y^2= 69 and xy=1 find 2x+3y​

Answer 1

Answer:

Hope it helps.............

Answer 2

Given:

• 4x² + 9y² = 69
• xy = 1

To find:

1. 2x + 3y = ?

Method:

Squaring (2x + 3y) and expand it using

(a + b)² = a² + b² + 2ab

(2x + 3y)² = (2x)² + (3y)² + 2(2x)(3y)

⇒ (2x + 3y)² = 4x² + 9y² + 12xy

⇒ (2x + 3y)² = 69 + 12(1)

⇒ (2x + 3y)² = 69 + 12

⇒ (2x + 3y)² = 81

⇒ (2x + 3y) = √81

⇒ (2x + 3y) = 9