Answer:
−1.9d + 4.6h − 18
Explanation:
8h − 6.9d − 18 + 5d − 3.4h
= 8h + −6.9d + −18 + 5d + −3.4h
[ Combine Like Terms ]
= 8h + −6.9d + −18 + 5d + −3.4h
= (−6.9d + 5d) + (8h + −3.4h) + (−18)
= −1.9d + 4.6h + −18
- PNW
Given the polynomial function

If (x-3) is a factor of P(x), then

, for some polynomial Q of 1st degree,
Then according to the factor theorem P(3)=0, because P(3)=(3-3)Q(x)=0*Q(3)=0.
Check

≠0
we see that P(3) is not 0, so (x-3) is not a factor of P(x).
Answer: no
Line 5 looks to be the best one