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3 years ago

X - 13 = x + 1 is it true

Mathematics

2 answers:

Nikolay [14]3 years ago

8 0

Answer:

Not true

Step-by-step explanation:

If we subtract x from both sides we geet -13 = 1, which of course is FALSE.

natulia [17]3 years ago

7 0

Answer:

No it is wrong

Step-by-step explanation:

let's say the number is 15 is a substract 13 I get 2 but let's take 15 again of I add one I have 16 so it's incorrect

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Anni [7]

Answer:

Step-by-step explanation:

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3 years ago

Suppose after 2500 years an initial amount of 1000 grams of a radioactive substance has decayed to 75 grams. What is the half-li

krok68 [10]

Answer:

The correct answer is:

Between 600 and 700 years (B)

Step-by-step explanation:

At a constant decay rate, the half-life of a radioactive substance is the time taken for the substance to decay to half of its original mass. The formula for radioactive exponential decay is given by:

$A(t) = A_0 e^{(kt)}\\where:\\A(t) = Amount\ left\ at\ time\ (t) = 75\ grams\\A_0 = initial\ amount = 1000\ grams\\k = decay\ constant\\t = time\ of\ decay = 2500\ years$

First, let us calculate the decay constant (k)

$75 = 1000 e^{(k2500)}\\dividing\ both\ sides\ by\ 1000\\0.075 = e^{(2500k)}\\taking\ natural\ logarithm\ of\ both\ sides\\In 0.075 = In (e^{2500k})\\In 0.075 = 2500k\\k = \frac{In0.075}{2500}\\ k = \frac{-2.5903}{2500} \\k = - 0.001036$

Next, let us calculate the half-life as follows:

$\frac{1}{2} A_0 = A_0 e^{(-0.001036t)}\\Dividing\ both\ sides\ by\ A_0\\ \frac{1}{2} = e^{-0.001036t}\\taking\ natural\ logarithm\ of\ both\ sides\\In(0.5) = In (e^{-0.001036t})\\-0.6931 = -0.001036t\\t = \frac{-0.6931}{-0.001036} \\t = 669.02 years\\\therefore t\frac{1}{2} \approx 669\ years$

Therefore the half-life is between 600 and 700 years

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3 years ago

How to memorize multiplication tables in one day?

padilas [110]

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3 years ago

Hi can you help me with this?

katrin [286]

Answer:

-3.9/1

Step-by-step explanation:

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3 years ago

Read 2 more answers

Which expression is equivalent to -1/2 (3- 2/5) ?

Pani-rosa [81]

Answer: The answer is -3 1/2 - 1/5

so it's C.

Step-by-step explanation:

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3 years ago