Answer:

Step-by-step explanation:
Given

Required
Determine the formula
First, we need to solve common difference (d)

Take n as 2



Represent each function as a sum of the previous





Represent the function as 

Reorder

Answer:
(negative 7 x + 4)(negative 7 x minus 4)
Step-by-step explanation:
Consider two real numbers a and b. A difference of squares involving a and b is usually given as;

The difference of the two squares above can be factored to yield;

This implies that in order to have the difference of squares we must have a product involving the difference and the sum of the numbers.
The expression;
(negative 7 x + 4)(negative 7 x minus 4) can also be written as ( 4 - 7x) ( -4 - 7x)
( 4 - 7x) ( -4 - 7x) = ( 4 - 7x) (-1( 4 + 7x)) = -1 *( 4 - 7x) ( 4 + 7x)
Expanding the last expression yields;
-1 (16 + 28x -28x - 49x^2) = -1 (16 - 49x^2) = 49x^2 - 16 which is in deed a difference of squares
The function given is a quadratic function, so the graph will be a parabola. It'll look similar to the photo attached. The minimum cost will be at the vertex of the parabola because that is its lowest point! To find the x-value of the vertex (which is what the question is looking for), use the vertex formula: x = -b/2a. The variable b is the coefficient of the x term in the function, and the variable a is the coefficient of the x² term. In this case, a = 0.125 and b = -5.
x = -(-5)/2(0.125)
x = 5/0.25
x = 20
So, 20 gas grills should be produced each day to maintain minimum costs. Hope that helps! :)