Is everything correct and how do you do the last part?

5 terms

Step-by-step explanation:

Yes, that's correct.  For the last part, set b₊₁ less than or equal to the error.

1 / (5ⁿ⁺¹ (n+1)!) ≤ 0.000005

5ⁿ⁺¹ (n+1)! ≥ 200,000

Use trial and error to find the value of n (notice that n starts at 0).

n = 0, 5ⁿ⁺¹ (n+1)! = 5

n = 1, 5ⁿ⁺¹ (n+1)! = 50

n = 2, 5ⁿ⁺¹ (n+1)! = 750

n = 3, 5ⁿ⁺¹ (n+1)! = 15,000

n = 4, 5ⁿ⁺¹ (n+1)! = 375,000

n = 4 is the fifth term.  So it takes 5 terms.

it would be 6xy and -16xy.