Which equation is a linear function? (a)y=2×-1 (b) y=x/2-5 (c) y=x power of 2+7 (d) 2/x+3

Why can't my rank go i have 1723 points, but my rank is only at ambitious, which is only 250 points! like, (p. s. i know this isn't related to math, but i just don't know why it's doing this and i would really appreciate if someone could tell me whats going on with this)

Renee hiked for 6 3 /4 miles. after resting, renee hiked back along the same route for 5 1 /4 miles. how many more miles does renee need to hike to return to the place where she started? represent your answer as a simplified mixed number, if necessary.

As a salesperson you get $23/ day and $3.60/each sale you make. if you want to make at least $84. in one day, how many sales would need to make? a 15b 16c 17d 18