To get this answer you need to simplify everything that you can. So basically, first you would combine 2x and x to get 3x+18. Note that you don't need to use the second part of the equation if you don't want to. Same with the third because they are all equal. Noting this, you subtract 18 from both sides of the equation leaving you with 75= 3x. Proceed to divide both sides by three and end with the answer 25=x.
I show an example in the picture below. If you know how to solve with Pythagorean theorem this problem should be fairly easy. All you have to do is make 2 triangles and solve for C. Once you solve for C for both triangles you should get 20 for one answer and 15 for the other answer. Then all you do is just add them together so your answer should be 35 feet.
