What numbers add up to 2 and multiply to get -15?

1 answer:

8 0

Set up 2 equations
A) x + y = 2
B) x * y =-15
We can change equation B into x = -15/y and substitute this into equation A

-15/y + y = 2

-15 + y^2 = 2y

y^2 -2y -15 =0
Factoring
(y +3) * (y-5) = 0

y = -3 and y =5
Then solve for x

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Nastasia [14]

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Step-by-step explanation:

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Explanation

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A country's population in 1991 was 136 million. In 2000 it was 141 million. Estimate the population in 2016 using the exponentia

katrin [286]

The answer is 150 million.

Step 1. Calculate the growth rate.
Step 2. Calculate the population number in 2014.

We will use the formula for exponential growth:
A = P * eⁿˣ
where:
A - the final amount (value)
P - the initial amount (value)
e - the mathematical constant (e ≈ 2.72)
n - the growth rate
x - the time

Step 1:
A = 141 million = 141 000 000
P = 136 million = 136 000 000
n = ?
x = 2000 - 1991 = 9
Therefore:
$141 000 000 = 136000 000 * e ^{n*9} \\ e ^{n*9} =141000 000 /136000000 \\ e ^{n*9} =1.04$

Logarithm both sides of the equation:
$ln(e ^{n*9})=ln(1.04) \\ n*9*ln(e) = ln(1.04) \\ 6n=ln(1.04) \\ n = \frac{ln(1.04)}{9} \\ n = \frac{0.04}{9} \\ n = 0.004$

Step 2:
Now when we know the growth rate, it is easy to estimate the population in 2016
A = ?
P = 141 000 000
n = 0.004
t = 2016 - 2000 = 16
$A = 141 000 000 * e ^{0.004*16} \\ A = 141000 000 * e^{0.0640} \\ A = 141000 000 * 1.066\\ A = 150306 000$

Thus, the population will be nearly 150 million in 2016

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marta [7]

8 days—> because if you 160 insurance is already added, subtract that to get your original price since that’s what is actually being counted.
So I did 760-160=600
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Also your answer is D.

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3 years ago

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NISA [10]

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