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Help With Math Homework Quadratic Functions

I need help in my math homework (Quadratic Functions)~~!?

A = 40x - x²

a. when you are using the fencing to bound all four sides, you will obtain maximum area by designing a square (so width is 20). This only works for fencing on all four sides.

to prove that in algebra, you would graph your function A = 40x - x², which looks like an upside down parabola, vertex (highest point) at x = 20. You could also do a table of values or use the derivative (calculus).

b. maximum area is 400 ft².

Can you help me on my math homework? It's on quadratic functions.?

There's only 5 questions that I don't get on my homework. Can you show your work step by step? I really appreciate it.

1) Ling is cutting carpet for a rectangular room. The area of the room is 324ft^2. The length of the room is 3 feet longer than twice the width. What should the dimensions of the carpet be? Answer this with numerical dimensions.

2)If the sides of a square are lengthened by 5 meters, the area becomes 121m^2. Find the length of the original square. Answer this with numerical dimensions.

3) A number subtracted from its square is 110. Find the number. Solve by setting up your equation, setting equal to 0, and factoring.

4) A rectangular pool measures 4yd by 5yd. A concrete deck of uniform width is constructed around the pool. The deck and pool together cover an area of 90yd^2. How wide is the deck? Answer this with numerical dimensions.

5) A rectangular window pane has an area of 15x^2 - 19x + 6. The width of the window pane is 3x-2. What is the length of the window pane in polynomial form?

Math homework help! quadratic functions!?

Represent cost C(x) by : C(x) = ax² + bx + c

We will arrive at three equations in a,b,c which we can solve.

(1) When x = 2 , C(2) = a(2²) + b(2) + c = 45

(2) When x = 4, C(4) = a(4²) + b(4) + c = 81

(3) When x = 10, C(10) = a(10²) + b(10) + c = 285

So, 4a + 2b + c = 45

16a + 4b + c = 81

100a + 10b + c = 285

Subtracting 1st equation from 3rd 100a - 4a + 10b - 2b + c - c = 285 - 45

giving 96a + 8b = 240

Now subtract 1st equation from 2nd 16a - 4a + 4b - 2b = 81 - 45

giving 12a + 2b = 36

We have two equations in a and b

96a + 8b = 240

12a + 2b = 36

Simplifying
12a + b = 30

6a + b = 18

Subtracting 2nd from 1st
12a - 6a + b - b = 30 - 18

6a = 12

a = 2

We can now substitute this to find b and obtain b = 6

Similarly substitute a,b in one of the original equations to find c = 25

The quadratic is : C(x) = 2x² + 6x + 25

When x = 6, C(6) = 2(6²) + 6(6) + 25 = 72 + 36 + 25 = 133

To make 10 calculators it costs $133.

Quadratic functions; homework help?

Let x = the amount they increase their charges by

Therefore the amount they charge this year = $20 + x
The number of customers they have this year = 70 - x

Therefore as their income = the charge multiplied by the number of customers,
Total income = (20 + x)*(70 - x)

Expand the brackets
Total Income = 1400 - 20x + 70x - x^2
Simplify -x^2 +50x + 1400

The maximum amount is where x = -b/2a
where b = 50 and is the coefficient of "x" and a = -1 and is the coefficient of "x^2"
Therefore max is where x = -50/-2
x = 25

a) Therefore the club should charge $20 + x = $20 + $25 = $45
b) With the price set at $45, the number of customers = 70 - 25 = 45
Maximum income = $45 * 45 = $2025

Quadratic functions math help?

I am so confused by my math homework, can somebody help me please?

1.Find a function whose graph is a parabola with vertex
(4, 6)
and that passes through the point
(3, −9).

2. A quadratic function is given.
g(x) = 2x2 + 8x + 13
(a) Express the quadratic function in standard form. (it wants you to complete the square)

3.A soft-drink vendor at a popular beach analyzes his sales records and finds that if he sells x cans of soda pop in one day, his profit (in dollars) is given by
P(x) = −0.001x2 + 5x − 1875.
What is his maximum profit per day? How many cans can he sell for max profit?

Thanks

Math help!!! quadratic function =[?

x² - 16x + 56 = 0

So we first complete the square

x² - 16x = -56

Take half of the middle term, square it, and add to both sides

x² - 16x + 64 = -56 + 64

(x - 8)² = 8

And so:

y = (x-8)² - 8

This is now in the form

y = a(x-h)² + k

where (h,k) is the vertex.

So the vertex is: (8, -8)

Have a good day!

Please help with my math homework. Quadratic functions and equations?

Erica has 20ft of chain link to make a rectangular cage for her pet rabbit. She will use all of the chain link, so the perimeter of the cage will be the same as the entire length.

Let w represent the width of the cage in feet use w to write an expression for the length of the cage(Hint: Use the perimeter formula P=2l+2w and solve for length).

Use your answer to question 2 to write a quadratic function for the cage's area, A, as a function of width, w.

Math Homework, Transforming Quadratic Functions.?

The position function for a free-falling object is given by

h(t) = - 16t² + v0t + h0

where h = height in ft., t = time in secs., v0 = initial velocity in ft./sec. and h0 = initial height in ft..

Position Function for Drop 1:

v0 = 0 ft./sec.
h0 = 400 ft.

h(t) = - 16t² + 400

Time to Impact: h(t) = 0:

- 16t² + 400 = 0
16t² = 400
t² = 400 / 16
t² = 25
t = √25
t = 5

Time to Impact for Drop 1 = 5 secs.
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Position Function for Drop 2:

h(t) = - 16t² + 1600

Time to Impact:

16t² = 1600
t² = 1600 / 16
t² = 100
t = √100
t = 10

Time to Impact for Drop 2 = 10 secs.
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Math Quadratic Function Question?

The points of intersection are found by solving

-3x^2 + 2x + 8 = x^2 - 4

-4x^2 + 2x + 12 = 0

2x^2 - x - 6 = 0


x = [1 +/- √( 1 - 4(2)(-6) ) ] / 2(2)

x = [ 1 +/- √( 49) ] / 4

x = -3/2 and x = 2


f(-3/2) = g(-3/2) = 9/4 - 4 = (9 - 16)/4 = -7/4

f(2) = g(2) = 4 - 4 = 0

The two points are (-3/2,-7/4) and (2,0)

Using the slope-intercept form and the point (2,0), you have

y = mx + b

0 = 2m + b


Using the slope-intercept form and the point (-3/2,-7/4) you have

-7/4 = -3m/2 + b

-7 = -6m + 4b

The system is

2m + b = 0
-6m +4b = -7

The solution is m = 1/2 and b = -1

So the equation is

y = (1/2)x - 1


Now check with a graphing calculator...

A quadratic function [math]3x^2 + px + q[/math] has the roots of -4 and 2, what is the value of p and q?

The quadratic function 3x^2+px+q has the roots of -4 and 2. What is the value of p and q?3x^2+px+q can be written as x^2+(p/3)x+(q/3) = 0(q/3) is the product of the roots and (p/3) is the sum or difference of the roots.So q/3 = (4)(-2) = -8, or q = -24p/3 = 4-2 = 2, or p = 6.Check: 3x^2+6x-24=03x^2+12x-6x-24 = 03x(x+4) -6(x+4) = 0(3x-6)(x+4) = 0x= 2 or -4. Correct.p = 6, q = -24.Another approach:3x^2+px+q = 0, has the roots of -4 and 2.Put x=-4 to get48–4p+q = 0 or-4p+q = -48…(1)Put x = 2 to get12+2p+q = 0, or2p+q = -12 …(2).Subtract (1) from (2) to get6p = 36 or p = 6.From (2), q = -12–2p = -12–12 = -24.So, p = 6, q = -24.

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