Answer:
525 x 1,050
A = 551,250 m²
Step-by-step explanation:
Let 'L' be the length parallel to the river and 'S' be the length of each of the other two sides.
The length of the three sides is given by:

The area of the rectangular plot is given by:

The value of 'S' for which the area's derivate is zero, yields the maximum total area:

Solving for 'L':

The largest area enclosed is given by dimension of 525 m x 1,050 and is:

The second one, and you as well ☺️
Answer: x < -3 or x > 5
Step-by-step explanation: Interval notation shows the values of x. X is less than -3, or greater than 5.
For

and

to be inversely proportional, there must be some constant

such that

Given that

when

, it follows that

Then when

, we have
By the Pythagorean Theorem:
L^2=20^2+15^2
L^2=400+225
L^2=625
L=25 m