If a and b are order and degree of differential equation y'' + (y')2 + 2y = 0, then value of 2a + 6b, is :

3 4 6 10

10

y'' + (y')2 + 2y = 0 highest order derivative ⇒ order = 2 = a max. power of it ⇒ degree = 1 = b  so 2a + 6b = 2 × 2 + 6 × 1 = 4 + 6 = 10