I think this is more of an opinion question. What someone could solve mentally may not be the same as someone else's.If it were my worksheet, I'd circle all of them but it may be different for you.
At your level, I'd probably circle:
54 - 10
93 - 20
and 39 - 2
Answer:
x=16/113
Step-by-step explanation:
look at them in order
Answer:
Step-by-step explanation:
The Answer is {x| x <-4 or x> 2}
21: The factors of 21 are 1,3,7,21