7. D
8. D
9. D
10.C
for 7 & 8 you use the equation

your points are (3,8) & (9,5)
so you plug the numbers in
y2= 5
y1=8
x2=9
x1=3
you subtract them get a fraction and that is your slope
9 & 10
use the equation

plug you numbers in for y1 and x2 m is your slope plug it in and that is your equation
9) 0.3
10) 4.1
11) 0.5
12) 4.8
13) 3.2
14) 1.6
15) 3.9
16) 1.5
Hope this helped, please mark brainliest
18 would have to be the mean because of the average