Thanks in advance, these problems have been stumping me. Please include answers though, I have tried to work it out, but need answers to see where I am going wrong/where I need to go.

1. Determine all solutions for X^4+2-3i

2. Forces of 60 and 100 pounds have a resultant force of 125 pounds, what is the angle between the vectors?

3. Consider a truck hat weighs 5000 pounds at an incline of 20 degrees. What is the braking force required to keep the truck from rolling down the hill?

4. Two forces with a direction of 30 degrees and 60 degrees and magnitudes of 5 and 13 respectively act on a point. Find the direction and magnitude of the resultant force.

See my answer to the same question by "Hujinson"