The expression "-2x" represents a linear function where the variable x is multiplied by -2. This means that for every increase in x, the value of the expression decreases by twice that amount. For example, if x is 1, then "-2x" equals -2. If x is 3, then "-2x" equals -6. In a graph, the line representing "-2x" slopes downward from left to right, indicating a negative relationship between x and the output. The y-intercept of this line is at the origin (0,0), meaning when x is 0, "-2x" is also 0.