Answer: We are given:
The height h of a guardrail = 106 centimeters
Absolute deviation = 7 centimeters
The absolute value inequality is 
To find the acceptable heights of a guardrail , we add and subtract absolute deviation(7) from the mean height(106)
The acceptable range of height is:
106 + 7 = 113
106 - 7 = 99
Acceptable heights are defined by

Therefore, the acceptable range of heights of a guardrail are 99 cm to 113 cm.