What is the independent variable? and Why? answer fast

Number of Days Absent | Marks
12 65
4 78
0 67
10 52
15 43
21 36
8 58
1 85
3 92
8 74
9 62
7 64
11 57
6 70
10 61
2 80

The surface area (sa) of a cube with a as the length of each of its sides is given by the formula . if the surface area is known, how can you rewrite the formula to find its side?

Aline on the wall and a line on the floor are skew. always, sometimes, or never?

Cassie is traveling 675 miles today to visit her brother and his family. so far, she has stopped for gas three times. at the first stop, she put in 7.1 gallons of gas and paid $23.79. at her second stop, she put in 5.8 gallons of gas and paid $19.08. and, at the third stop, 6.6 gallons and paid $20.39. at which stop did casey pay the most for gas?