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Novosadov [1.4K]
2 years ago
12

Which statements are true about the ordered pair (-1,-4) and the system of equations? x-y=3 and 7x-y=-3

Mathematics
1 answer:
alexandr402 [8]2 years ago
8 0

Answer:

when (-1, -4) is substituted into the first equation it's true

when (-1, -4) is substituted into the second equation it's true

the ordered pair (-1, -4) is a solution to the systems of equation

Step-by-step explanation:

original equation

x-y=3

multiply both sides by 7

7x-7y = 21

add 7y to both sides

7x=7y + 21

substitute into second equation

(7y+21)-y=-3

simplify

6y+21=-3

subtract 21 from both sides

6y=-24

y=-4

substitute y into original equation

x-(-4) = 3

cancel out negative signs

x+4=3

subtract -4 from both sides

x=-1

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Answer:

Step-by-step explanation:

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the population P (t) of a culture of bacteria is given by P (t) =-1710t +92,000t+10,000, where t is the time in hours since the
Akimi4 [234]

The question might have some mistake since there are 2 multiplier of t. I found a similar question as follows:

The population P(t) of a culture of bacteria is given by P(t) = –1710t^2+ 92,000t + 10,000, where t is the time in hours since the culture was started. Determine the time at which the population is at a maximum. Round to the nearest hour.

Answer:

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Step-by-step explanation:

Equation of population P(t) = –1710t^2+ 92,000t + 10,000

Find the derivative of the function to find the critical value

dP/dt = -2(1710)t + 92000

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-3420t + 92000 = 0

92000 = 3420t

t = 92000/3420 = 26.90

Check if it really have max value through 2nd derivative

d(dP)/dt^2 = -3420

2nd derivative is negative, hence it has maximum value

So, the time when it is maximum is 26.9 or 27 hours

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