Answer:

Step-by-step explanation:
Expression for the rectangular area and perimeter are, respectively:


After some algebraic manipulation, area expression can be reduce to an one-variable form:


The first derivative of the previous equation is:

Let the expression be equalized to zero:


The second derivative is:

According to the Second Derivative Test, the critical value found in previous steps is a maximum. Then:

The maximum area is:


<h3>47 × 63 = <u>2961</u></h3>
<h3>... Hope this will help... </h3>
<h3>U can also verify the answer using a calculator </h3>
Explanation:
Since we have given that

Now, we have to prove it as

Now, start the iterations:

So, first blank will be filled with

Second blank will be filled with

Hence proved.
Answer:
y = 1.25
Step-by-step explanation:
Use the direct variation equation y = kx, and solve for k:
y = kx
-10 = k(40)
-0.25 = k
So, the equation is y = -0.25x. Solve for y when x = -5
y = -0.25x
y = -0.25(-5)
y = 1.25
So, y = 1.25 when x = -5