<span>This property is called associativity. It shows that it doesn't matter whether you perform the sum on the first two numbers and then the third, or on the second two and then the first, because you will get the same answer either way. That is because addition is associative.</span>
Area=length*width
let the sides perpendicular to the river be x
then the side parallel to the river is 4,700-2x
A(x)=x(4700-2x)
A(x)=4700x-2x^2
This a quadratic function with a=-2 and b=4700
thus
Maximum area occurs where x=-b/2a=-4700(-2*2)=1,175 ft
length=4700-2(1175)=2,350 ft
I dont know the answer sorry am a biginner