Answer:

Step-by-step explanation:
In a quadratic equation in the Standard form

You need to remember that "a", "b" and "c" are the numerical coefficients (Where "a" is the leading coefficient and it cannot be zero:
).
You can observe that the given quadratic equation is written in the Standard form mentioned before. This is:

Therefore, you can identify that the values of "a", "b" and "c" are the following:

(x/100-1)(x/100+1)=kx^2-1
(x/100-1)(x/100+1)=(x/100)^2 - 1^2 because it's a difference of squares ( (a-b)(a+b) = a^2-ab+ab-b^2 = a^2 - b^2):
(x/100)^2 - 1^2=kx^2 - 1
(x/100)^2 - 1=kx^2 - 1
(x/100)^2=kx^2
(x^2)/(100^2)=kx^2
1/(100^2)=k
1/10000=k
k=0.0001
Answer:
(a) 
(b) 7 hours.
Step-by-step explanation:
(a) Let x be the number of hours and y is the total cost.
We have been given that Beatrice and her friends charge $8 per hour of babysitting, so the charges for x hours of babysitting will be 8x.
As they also charge a mandatory $5 per day fee for each child for snacks, so the total charges for babysit each day will be charges for x hours of babysitting plus mandatory charge.
We can represent this information in an equation as:

Therefore, the equation
represents the total cost of using Beatrice’s babysitting service each day.
(b) To find the number of hours Beatrice babysit the daughter, we will substitute y = 61 in our equation and solve for x.

Let us subtract 5 from both sides of our equation.


Let us divide both sides of our equation by 8.


Therefore, Beatrice babysit 7 hours the daughter.
Expression for part c is missing.
Answer:
$4000 net profit
Step-by-step explanation:
Profit adds to the net revenue, while loss subtracts from it.
So 6500 is positive but 1200 and 1300 are negative.
+6500 - 1200 - 1300 = 5300 - 1300 = 4000
$4000 profit