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4 years ago

What are the solutions to 2x^2-4x-30=0

Mathematics

1 answer:

oksano4ka [1.4K]4 years ago

5 0

Answer:

ill try 2x2-4x-30=0

Two solutions were found :

x = 5

x = -3

Step by step solution :

Step 1 :

Equation at the end of step 1 :

(2x2 - 4x) - 30 = 0

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6.45$ for 3 divide 15.05

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4 years ago

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2. Suppose 27 blackberry plants started growing in a yard. Absent constraint, the blackberry plants will spread by 80% a month.

Marta_Voda [28]

Explanation

The question indicates we should use a logistic model to estimate the number of plants after 5 months.

This can be done using the formula below;

$\begin{gathered} P(t)=\frac{K}{1+Ae^{-kt}};A=\frac{K-P_{0_{}}}{P_0}_{} \\ \text{From the question} \\ P_0=\text{ Initial Plants=27} \\ K=\text{Carrying capacity =140} \end{gathered}$

Workings

Step 1: We would need to get the value of A using the carrying capacity and initial plants that started growing in the yard.

This gives;

$\begin{gathered} A=\frac{140-27}{27} \\ A=\frac{113}{27} \end{gathered}$

Step 2: Substitute the value of A into the formula.

$P(t)=\frac{140}{1+\frac{113}{27}e^{-kt}}$

Step 3: Find the value of the constant k

Kindly recall that we are told that the plants increase by 80% after each month. Therefore, after one month we would have;

$\begin{gathered} P(1)=27+(\frac{80}{100}\times27) \\ P(1)=\frac{243}{5} \end{gathered}$

We can then have that after t= 1month

$\begin{gathered} \frac{140}{1+\frac{113}{27}e^{-k\times1}}=\frac{243}{5} \\ Flip\text{ the equation} \\ \frac{1+\frac{113}{27}e^{-k}}{140}=\frac{5}{243} \\ 243(1+\frac{113}{27}e^{-k})=700 \\ 243+1017e^{-k}=700 \\ 1017e^{-k}=700-243 \\ 1017e^{-k}=457 \\ e^{-k}=\frac{457}{1017} \\ -k=\ln (\frac{457}{1017}) \end{gathered}$

Step 4: Substitute -k back into the initial formula.

$\begin{gathered} P(t)=\frac{140}{1+\frac{113}{27}e^{\ln (\frac{457}{1017})t}} \\ =\frac{140}{1+\frac{113}{27}(e^{\ln (\frac{457}{1017})})^t} \\ P(t)=\frac{140}{1+\frac{113}{27}(\frac{457}{1017}^{})^t} \\ \end{gathered}$

The above model is can be used to find the population at any time in the future.

Therefore after 5 months, we can estimate the model to be;

$\begin{gathered} P(5)=\frac{140}{1+\frac{113}{27}(\frac{457}{1017}^{})^5} \\ P(5)=\frac{140}{1.07668} \\ P(5)=130.029\approx130 \end{gathered}$

Answer: The estimated number of plants after 5 months is 130 plants.

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1 year ago

Max constructed a scale model of the Eiffel tower. The base area of the model is 0.25 square meters, while the base area of the

Vanyuwa [196]

Answer:

1:250

Step-by-step explanation:

$\sqrt{15625/0.25}$

= $\sqrt{62500}$

=250

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4 years ago

Distance between the points (-4,6) and (3,-7)

gtnhenbr [62]

Answer:19

Step-by-step explanation:first make or find a grid chart then label them and make the x axis and y axis then count up the blocks they are apart and you’ll get 19( I hope)

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3 years ago

(Please Help Will mark brainliest) What is the total surface area of the triangular prism?

PolarNik [594]

Answer:

63m^2

Step-by-step explanation:

Find the area of each base

2.5(10)= 25

1.5(10) = 15

2(10) = 20

Add them together

20 + 15 + 25 = 60

Now find the area of the triangles at each side

2(1.5)(1/2) = 1.5

Since there are two triangles, multiply the area by 2

1.5(2) = 3

Add the areas together

60 + 3 = 63

There's your answer

4 0

3 years ago

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