HELP PLEASE! 20 points and brainliest! A population of horned vipers in the Sahara is experiencing exponential decay. There were 840 vipers initially, and after a year there were 798 vipers. Approximately how many years need to pass before a third of the initial population is gone? Justify your reasoning. Answer in complete sentences.

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1/4 because there is 4 grades.

it has changed from the width and the height.

step-by-step explanation:

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15