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3 years ago

1 Solve this quadratic using two different methods. Show both methods. x2 + 4x - 5 = 0

Mathematics

1 answer:

AURORKA [14]3 years ago

6 0

Answer:

x = -5 or x = 1

Step-by-step explanation:

$x^{2} + 4x - 5 = 0\\(x+5)(x-1)=0\\$

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Someone tell me how to do this

nirvana33 [79]

So you first make 1 7/9 into 16/9
then you do 16/9 - 4/9 which equals to 12/9 then you simplify and get 4/3 then simplify again into 1 1/3

3 0

3 years ago

Please explain I really need help

velikii [3]

Answer:

1. 1343 years

2. 9 hours

3. 39 years

Step-by-step explanation:

1. Given, half-life of carbon = 5730 years.

∴ λ = 0.693/half-life of carbon = 0.693/5730 = 0.000121

If N₀ = 100 then N = 85

Formula:- N = N₀*e^(-λt)

∴ 85 = 100 * e^(-0.000121t)

∴㏑(-0.85)=-0.000121t

∴ t = 1343 years

2. Given half-life of aspirin = 12 hours

λ = 0.693/12 = 0.5775

Also N₀ = 100 then 70 will disintegrate and N = 30 will remain disintegrated.

∴ 70 = 100 *e^(-0.05775t)

0.70 = e^(-0.05775t)

㏑(0.70) = -0.05775t

∴ t = 9 hours

3. The population of the birds as as A=A₀*e^(kt)

Given that the population of birds fell from 1400 from 1000, We are asked how much time it will take for the population to drop below 100, let that be x years.

The population is 1400 when f = 0, And it is 1000 when f = 5

We can write the following equation :

1400 = 1000e^(5t).

∴1400/1000 = e^(5k)

∴ k = ㏑(1.4)/5

We need to find x such that 1400/100 = e^(xk)

14 = e^(xk)

∴ x = 39 years

5 0

3 years ago

Prove that the sum of all natural numbers is -1/12.

ankoles [38]

This is not true. The infinite series

$\displaystyle\sum_{n=1}^\infty n$

converges if and only if the sequence of its partial sums converges. The $k$ -th partial sum is

$\displaystyle\sum_{n=1}^kn=\frac{k(k+1)}2$

but clearly this diverges as $k$ gets arbitrarily large.

5 0

3 years ago

Coleen made 1,000 bracelets to sell at a flea market. She sold each bracelet for $5.50. If she sold all of the bracelets, how mu

Alex_Xolod [135]

Answer:

$5.500

Step-by-step explanation:

$5.50x1000= $5.500

8 0

2 years ago

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