Question

If 3x+2y=12 and xy=6 find 9x^2+4y^2.

Plz give Step by step explanation.​

Answer 1

GIVEn

If 3x+2y=12 and xy=6 find 9x^2+4y^2.

SOLUTIOn

• 3x + 2y = 12
• xy = 6

Squaring both side

→ (3x + 2y)² = (12)²

→ (3x)² + (2y)² + 2*3x*2y = 144

→ 9x² + 4y² + 12xy = 144

→ 9x² + 4y² + 12*6 = 144

→ 9x² + 4y² + 72 = 144

→ 9x² + 4y² = 144 - 72

→ 9x² + 4y² = 72

SOMe IDENTITIEs

• (a - b)² = a² + b² - 2ab
• a² - b² = (a + b)(a - b)
• a³ - b³ = (a - b)(a² + ab + b²)