Answer:
D. infrared.
Explanation:
Wireless technology for communication uses electromagnetic wave to transmit signals between location. It eliminates the need of cables for connecting network devices.
In previous wireless technology implementation, Infrared rays were used (in tv remotes), which needed to be in the line of sight to its destination. Although it was fast, it has many limitations for a long-haul transmission like its short transmission range, easily blocked by objects and its uni-directional properties.
Answer:
14
Explanation: The reason why is because adding a negative is pretty much subtracting by 2. 9-2=7. Then multiply 7 by 2 like add 7 to 7 and you get 14.