Answer:
838.88
Step-by-step explanation:
-55
2nd term=> -1 + -2 × (2 - 1)
3rd term=> -1 + -2 × (3 - 1)
:
28th term=> -1 + -2 × (28 - 1)
=> -1 - 54 = -55
= 18x + 4y hope this helps :)