Question

If a^2 + b^2 = 8 and ab = 3, find the value of 3(a + b) ^2 - 2(a - b)^2

Answer 1

Here is your answer -Given - a²+b²= 8ab = 33(a+b)²- 2(a-b)² = ?We know that -(a+b)² = a²+b²+2abSo putting the value of a+ b and ab in the given equation (a + b) ² = a²+b²+2ab 8 + 2×3 8 + 6 14Now , (a - b)²= a²+ b²-2ab = 8 - 2 × 3 = 8 - 6 = 2Now 3(a+b)²- 2(a-b)² = 3 × 14 - 2 × 2 = 42 - 4 = 38