The total number of ways to pick 2 balls from 10 is \( \binom{10}{2} = 45 \).
The number of favorable outcomes (picking 2 white balls) is \( \binom{6}{2} = 15 \). Thus, the probability is \( \frac{15}{45} = \frac{1}{3} \).
If \[ f(x) = \int \frac{1}{x^{1/4} (1 + x^{1/4})} \, dx, \quad f(0) = -6 \], then f(1) is equal to:
If the system of equations \[ (\lambda - 1)x + (\lambda - 4)y + \lambda z = 5 \] \[ \lambda x + (\lambda - 1)y + (\lambda - 4)z = 7 \] \[ (\lambda + 1)x + (\lambda + 2)y - (\lambda + 2)z = 9 \] has infinitely many solutions, then \( \lambda^2 + \lambda \) is equal to: