Assume that x is a char variable that has been declared and already given a value. Write an expression whose value is true if and only if x is a decimal digit (0-9). 2) Assume that x is a char variable that has been declared and already given a value. Write an expression whose value is true if and only if x is an octal (Base 8) digit (0-7). 3) Assume that x is a char variable that has been declared and already given a value. Write an expression whose value is true if and only if x is alphanumeric, that is either a letter or a decimal digit. 4) Assume that x is a char variable that has been declared and already given a value. Write an expression whose value is true if and only if x is an hexadecimal (Base 16) digit (0-9 plus A-F or a-f). 5) Assume that x is a char variable that has been declared and already given a value. Write an expression whose value is true if and only if x is NOT a upper-case letter. 6) Assume that x is a char variable that has been declared and already given a value. Write an expression whose value is true if and only if x is NOT a letter. 7) Clunker Motors Inc. is recalling all vehicles from model years 2001-2006. A bool variable named norecall has been declared. Given an int variable modelYear write a statement that assigns true to norecall if the value of modelYear does NOT fall within the recall range and assigns false otherwise. Do not use an if statement in this exercise! 8) Clunker Motors Inc. is recalling all vehicles from model years 2001-2006. A bool variable named recalled has been declared. Given an int variable modelYear write a statement that assigns true to recalled if the value of modelYear falls within the recall range and assigns false otherwise. Do not use an if statement in this exercise!