Answer:
x = 225.16 feet
Step-by-step explanation:
Given that,
The angle between the piling and the pier is 60°.
A surveyor has set up his transit on one side of the lake 130 feet from a piling that is directly across from a pier on the other side of the lake.
We need to find the distance between the piling and the pier. Let the distance be d. Using the trigonometry to find it as follows :

So, the required distance is 225.16 feet.

5x -2y = -10 .....1
3x + 6y =66......2
on multiplying eq. 1 by 3
5x -2y = -10 .....1 ×3
15x -6y =-30
now subtract both equations ,
15x -6y =-30
3x + 6y =66
-___-_____-_
12x =-96
x= -8.
putting value of x in eq 1
5×8 -2y =-10
40 -2y =-10
40-10=2y
50=2y
25=y.
The formula is a^2-b^2=(a-b)(a+b)
So answer is (5x-3)(5x+3)
Zero because 60 plus negative 60 equals 0