Answer:
a1 = -7
d = -10
Step-by-step explanation:
Look at the points, you first point (1,-7) where a1 is 1 and that also means -7
Same for d go to the second point (2,-17) now add a1 from that
-17+7 = -10 so to get from -7 to -17 you had to add -10 <--- that is your d!
Goodluck