The line under the less than sign means "possibly equal."
Therefore, the comparison is between: 2x <= 10 which means "twice x is either less than or equal to 10" and 2x < 10 which means that "twice x is strictly less than 10 (and never equal to 10)."
Since x = 5, 2x = 10 which makes the first inequality true and makes the second inequality false.