Question

If
${a}^{2} + {b}^{2} = 9$
and
ab=4

Then find the value of
$3({a + b}^{2} ) - 2( {a - b}^{2} )$
PLEASE HELP ME
AS SOON AS POSSIBLE
​

Answer 1

Correct Question :- if a² + b² = 9 and ab = 4, find the value of 3(a+b)² - 2(a - b)² ?

Solution :-

→ 3(a + b)² - 2(a - b)²

using :-

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

→ 3(a² + b² + 2ab) - 2(a² + b² - 2ab)

→ 3a² + 3b² + 6ab - 2a² - 2b² + 4ab

→ (3a² - 2a²) + (3b² - 2b²) + (6ab + 4ab)

→ a² + b² + 10ab

→ (a² + b²) + 10ab

Putting value of a² + b² and ab now,

→ 9 + 10*4

→ 9 + 40

→ 49 (Ans.)