Question 129723: I have some problems I got wrong on my test. Please explain step by step what I should have done. I am allowed four, so here they are.
1.) Pizza Unlimited has the following prices for pizzas. Price is related to diameter by a quadratic equation. Fit a quadratic equation into the data points (8, 3.39), (12, 5.12), and (16, 7.29).
Diameter Price
8 inch $3.39
12 inch $5.12
16 inch $7.29
A.) Price =what quadratic equation?
B.) Using the equation find the price of a 14 inch pizza.
I know the answers, but I did the problem wrong, will you please show me the steps? How did they get the equation?
Answer A: 0.01375x^2 +0.1575x+1.25
Answer B: 14 inch pizza costs $ 6.15
2.) Solve for x. (x-6)^2 + (x+1)^2 = 0
The solutions are 5 + 7 i /2, 5-7 i/2
How do I know when to place the “ I “ one there?
Please show the step by step way to get this solution.
3.) What is the maximum product of two numbers whose sum is -6? What numbers yield this product? The max product is?
I put the max product at 9 (incorrect) and the numbers yielding this product at -3, -3 (correct)
However when I did the same problem with -16 instead of -6, I got 49 for the max product and it was correct. I thought the max product was the number in question squared. How do I get the max product?
4.) Solve the formula for the given number. Assume all variables represent positive numbers.
(N=n^2 – 19 n)/6; for n
I got n = (19 + sqrt sign 361 + 36 N)/2 (incorrect)
The answer is n = (19 + sqrt sign 361 + 24 N)/2
What did I do wrong, please show me the steps.
Thanks for all your help!!!!!!!!!! :o)
Found 2 solutions by stanbon, chitra:
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! I have some problems I got wrong on my test. Please explain step by step what I should have done. I am allowed four, so here they are.
1.) Pizza Unlimited has the following prices for pizzas. Price is related to diameter by a quadratic equation. Fit a quadratic equation into the data points (8, 3.39), (12, 5.12), and (16, 7.29).
Diameter Price
8 inch $3.39
12 inch $5.12
16 inch $7.29
A.) Price =what quadratic equation?
--------------
Substitute the three x/y pairs into the quadratic form: y = ax^2+bx+c
to get three equations in the three unknows a,b,and c
Solve the three equations for a,b, and c
------------------------------------------------
B.) Using the equation find the price of a 14 inch pizza.
If the equation is f(x) = 0.01375x^2+0.1575x+1.25, find f(14)
to find the price of a 14 in. pizza.
----------------------
I know the answers, but I did the problem wrong, will you please show me the steps? How did they get the equation?
Answer A: 0.01375x^2 +0.1575x+1.25
Answer B: 14 inch pizza costs $ 6.15
=============================================
2.) Solve for x. (x-6)^2 + (x+1)^2 = 0
You get x^2-12x+36 + x^2+2x+1 = 0
2x^2-10x+37 = 0
x = [10 +- sqrt(100-4*2*37)]/4
x = [10 +- sqrt(-196)]/4
x = [10 +- 14i]/4
You get that "i" because i is the square root of -1.
---------------------------------
The solutions are 5 + 7 i /2, 5-7 i/2
How do I know when to place the “ I “ one there?
Please show the step by step way to get this solution.
=============================
3.) What is the maximum product of two numbers whose sum is -6? What numbers yield this product? The max product is?
I put the max product at 9 (incorrect) and the numbers yielding this product at -3, -3 (correct)
However when I did the same problem with -16 instead of -6, I got 49 for the max product and it was correct. I thought the max product was the number in question squared. How do I get the max product?
--------
Let one of the numbers be "x"; If the other number is "y"
the sum, x+y = -6
y = -(x+6)
---------
Their product is P(x) = x [-(x+6)]
Then P(x) = -x^2-6x
This is a quadratic with a = -1 and b = -6
The max occurs when x = -b/2a = 6/-2 = -3
Since x+y = -6
-3+y = -6
y = -3
And the product is 9
=========================
4.) Solve the formula for the given number. Assume all variables represent positive numbers.
(N=n^2 – 19 n)/6; for n
I got n = (19 + sqrt sign 361 + 36 N)/2 (incorrect)
The answer is n = (19 + sqrt sign 361 + 24 N)/2
What did I do wrong, please show me the steps.
Thanks for all your help!!!!!!!!!! :o)
------------------
I can't follow what you mean here.
=====================================
Cheers,
Stan H.
Answer by chitra(359) (Show Source):
|
|
|
