How do you solve -2x + 6 less than or equal to 4x + 18 ?

Alex measured the length of an item to be 3.7 cm. the actual length is 3.5 cm. what is alex’s percent error?

Me d is also an option but i couldn't get it in the picture

Aresearch study is done to find the average age of all u.s. factory workers. the researchers asked every factory worker in ohio what their birth year is. this research is an example of a census survey convenience sample simple random sample