Let a = {2 less than or equal to x less than or equal to 7}, B = {x greater than a}, C = {K + 1 less than or equal to x less than or equal to 2K + 3} 1, if the empty set is a proper subset of (a intersection B), The known set a = {2 less than or equal to x less than 7}, B = {x greater than a}, C = {K + 1 less than or equal to x less than or equal to 2K + 3} 1. If the empty set is a proper subset of (a intersection b), the value range of a is obtained 2. If a and C = a, find the value range of K

Let a = {2 less than or equal to x less than or equal to 7}, B = {x greater than a}, C = {K + 1 less than or equal to x less than or equal to 2K + 3} 1, if the empty set is a proper subset of (a intersection B), The known set a = {2 less than or equal to x less than 7}, B = {x greater than a}, C = {K + 1 less than or equal to x less than or equal to 2K + 3} 1. If the empty set is a proper subset of (a intersection b), the value range of a is obtained 2. If a and C = a, find the value range of K

1. It means that the intersection of a and B is not an empty set. Use the number axis to mark the range of a set, we can know that a = 2K + 3, and the solution is k = 2 and 2K + 3