1) int[] mas = {5, 4, 8, 9, 7, 3, 4};
2)
int[] array = mas.Select(p => p).Where(p => p == 9).ToArray();
1) int[] mas = {5, 4, 8, 9, 7, 3, 4};
2)
int[] array = mas.Select(p => p).Where(p => p == 9).ToArray();