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Leni [432]
3 years ago
11

Solve the quadratic equation by completing the square. x² + 4x - 3=0

Mathematics
1 answer:
Varvara68 [4.7K]3 years ago
7 0

Answer:

Ur answer is D

Step-by-step explanation:

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A company's profit C (in thousands of dollars) can be modeled by the polynomial function C = - 5x ^ 3 + 6x ^ 2 + 15x , where x i
steposvetlana [31]

Answer:

849 items.

Step-by-step explanation:

Given that the profit C (in thousands of dollars) for x thousands of items related as

C = - 5x ^ 3 + 6x ^ 2 + 15x \\\\\Rightarrow -5x^3+6x^2+15x -C=0\cdots(i)

As the profit is $14,000 for producing 2000 items, so

C= 14 thousand dollars and

x= 2 thousand items.

Putting C= 14 in the equation ( we have),

-5x^3+6x^2+15x -14=0\cdots(ii)

Now, x=2 is one of the solutions to the equation (ii), so (x-2) is a factor of the equation (ii), we have

(x-2)(-5x^2-4x+7)=0 \\\\\Rightarrow x-2=2 \; or \; -5x^2-4x+7=0

We have the given solution for x-2=0, so sloving -5x^2-4x+7=0 for other solutions.

-5x^2-4x+7=0 \\\\\Rightarrow x= \frac {-(-4)\pm \sqrt {(-4)^2-4\times (-5)7}}{2\times (-5)} \\\\\Rightarrow x= \frac {4\pm \sqrt {156}}{2\times (-5)} \\\\\Rightarrow x= \frac {4\pm 12.49}{2\times (-5)} \\\\\Rightarrow x = \frac {4+ 12.49}{2\times (-5)}, \frac {4- 12.49}{2\times (-5)} \\\\\Rightarrow x = -1.649, 0.849

As the number of items cant be negative, so x= 0.849 thousand is the other number of items.

Hence, the other number of items for the same profit is 849 items.

4 0
3 years ago
The number of bacteria (b) in a batch of refrigerated food is given by the function b(t) = 20t2 − 70t + 300, where t is the temp
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1. Collect like terms
20t^2 + (-70 + 300)
2. Simplify
20t^2 + 230
4 0
3 years ago
I NEED HELP WITH 5,6,7,8
NARA [144]

Answer:

2,78,10,7

Step-by-step explanation:

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3 years ago
A lender wil verity and carefully consider your income before approving you for a loan because
ExtremeBDS [4]
A. They need to be sure you will be able to pay the loan back
8 0
3 years ago
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Using a directrix of y = −3 and a focus of (2, 1), what quadratic function is created?
bazaltina [42]
<span>f(x) = one eighth (x - 2)^2 - 1
   Since a parabola is the curve such that all points on the curve have the same distance from the directrix as the distance from the point to the focus.With that in mind, we can quickly determine 3 points on the parabola. The 1st point will be midway between the focus and the directrix, So: (2, (1 + -3)/2) = (2, -2/2) = (2,-1). The other 2 points will have the same y-coordinate as the focus, but let offset on the x-axis by the distance from the focus to the directrix. Since the distance is (1 - -3) = 4, that means the other 2 points will be (2 - 4, 1) and (2 + 4, 1) which are (-2, 1) and (6, 1). The closest point to the focus will have the same x-coordinate as the focus, so the term will be (x-2)^2. This eliminates the functions "f(x) = -one eighth (x + 2)^2 - 1" and "f(x) = -one half (x + 2)^2 - 1" from consideration since their x term is incorrect, leaving only "f(x) = one eighth (x - 2)^2 - 1" and "f(x) = one half (x - 2)^2 + 1" as possible choices. Let's plug in the value 6 for x and see what y value we get from squaring (x-2)^2. So: (x-2)^2 (6-2)^2 = 4^2 = 16 Now which option is equal to 1? Is it one eighth of 16 minus 1, or one half of 16 plus 1? 16/8 - 1 = 2 - 1 = 1 16/2 + 1 = 8 + 1 = 9 Therefore the answer is "f(x) = one eighth (x - 2)^2 - 1"</span>
3 0
4 years ago
Read 2 more answers
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