Which of the following is a linear expression in one variable?
An algebraic expression which has only one variable and the highest power of that variable is "one" is termed as a linear expression in one variable. Here, only (x+5) is a linear expression in one variable.
(x+5=0) is a linear equation as it contains an 'equal to' symbol. It is not an algebraic expression.
(x2+3=0) is an equation, the highest power of the variable is two. Hence, it is not a linear expression.
(xy+5) is an algebraic expression but it is not a linear expression in one variable as it contains two variables.