The correct answer is - protection of the cargo.
The wicker fence on the ships of the Phoenicians had the purpose to protect the cargo. Since the sea waters are not always calm, and very often, out of nowhere, a storm can emerge and contribute to bigger waves, as well as rocking of the ship itself, the Phoenicians invented a simple trick, and that was the wicker fence. With it on place, the cargo was safe on the boat, and it was not able to slip away and be lost in the sea.
Explanation:
everything can be found in the picture
You can use substitution method
x - y = 7
(x+y)^2=289
So
Since the square of their sum is 298, their sum without being squared is the square root of 289.
Hence,
x - y = 7
x + y = 17
By subtracting you get the following:
= (0) -2(y)=-10
So -2y=-10
y=-10/-2
y=5
Now, plug in y in both equations to get x
x - (5) = 7
x + (5) = 17
Multiply each equation with its opposite y variables
(5) x - (5) = 7
(-5) x + (5) = 17
= 5x -25 = 35
-5x -25 = -85
Now subtract the equations
= 10x + (0) = 120
10x = 120
x = 120/10
x = 12