If a and b are the roots of the equation x2

Home » Aptitude » Quadratic Equation » Question

If a and b are the roots of the equation x² - 6x + 6 = 0, find the value of 2(a² + b²).

1. 40
2. 42
3. 48
4. 46
5. None of the above

Correct Option: C

a and b are the roots of the equation
x² - 6x + 6 = 0
∴ a + b = -B/A = 6 and ab = C/A = 6
We know that,
a² + b² = (a + b)² - 2ab
= (6)² - 2 x 6 = 36 - 12 = 24
∴ 2(a² + b²) = 2 x 24 = 48