First find all possible rational roots. To do this, find all the factors of the lowest order coefficient and the highest order coefficient. For #1, the highest order coefficient is 1 because the x^3 doesn't have a number in front of it. The lowest order coefficient is 30.
Here are all the factors:
Factors of 1 are: 1
Factors of 30 are: 1, 2, 3, 5, 6, 10, 15, 30
Now divide each factor of 30 (positive and negative), and divide them by each factor of 1.
Now we perform synthetic division like you have started to do. Try dividing the polynomial by each possible root. If the result has a remainder, that possible root does NOT work. Try another possible root. If there is not a remainder, you have found one of the roots.
For example, when dividing x^3 - 4x^2 -11x + 30 by the possible root 2, we get x^2 - 2x - 15 without a remainder. That means 2 is a root. From here we can factor the result to (x-5)(x+3).
Since he has to pay back $72 split four ways just divide that to find out that your answer is 18
Considering there are about 4 weeks in a month give or take you can just multiply 3 by four to get your first month of $12 to everyone so then you add two more weeks which is $6 more you get your answer of a month and a half to pay $18 to each person.
If the butterfly travels 6000m in 30 seconds just double everything to get 12,000m per minute.
If you want an easier part for 9 just add 13 to 286 to find out the other number to get 299 as your answer 299-13=286