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2 years ago

List all number sets that apply to each number.

Mathematics

1 answer:

Airida [17]2 years ago

8 0

Yeah i agree with them y=10

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−1/2(7z+4)+1/5(5z−15)

Tanya [424]

Answer:

Step-by-step explanation:

-7z/2 - 2 + z -3

=-5 - 5z/2

5 0

2 years ago

Which statement about the function is true?

krok68 [10]

Answer:

The function is negative for all real values of x where -6< x < -2

Step-by-step explanation:

Given f(x) = (x + 2)(x + 6)

The graph of the function is as shown in the attached figure.

As shown, we can deduce the following:

The function is positive for all real values of x where x > -2 and x < -6

The function is zero at x = -2 and x = -6

The function is negative for all real values of x where -6 < x <-2

Compare the observations to the given statements:

So, The true statement is The function is negative for all real values of x where -6 < x <-2

7 0

2 years ago

The height above the surface of the Earth (in meters) of a rock thrown into the air at 10 m/s after x seconds is given by f(x)

Sonbull [250]

Answer:

Rock travels about 8.2x²meters higher on the moon than on the Earth.

Step-by-step explanation:

Expression showing the height of a rock thrown into the air at Earth is,

f(x) = -9.8x² + 10x + 1.5

Similarly, expression showing the height of rock thrown on the moon is,

g(x) = -1.6x² + 10x + 1.5

Difference in the height of the rock thrown on moon = g(x) - f(x)

= (-1.6x² + 10x + 1.5) - ( -9.8x² + 10x + 1.5)

= -1.6x² + 9.8x² + 10x - 10x + 1.5 - 1.5

= 8.2x²

Therefore, rock travels about 8.2x²meters higher on the moon than on the Earth.

8 0

3 years ago

The temperature, H, in °F, of a cup of coffee t hours after it is set out to cool is given by the following equation. H = 70 + 1

Alex73 [517]

Answer:

The temperature a t = 0 is 190 °F

The temperature a t = 1 is 100 °F

The temperature a t = 2 is 77.5 °F

It takes 1.5 hours to take the coffee to cool down to 85°F

It takes 2.293 hours to take the coffee to cool down to 75°F

Step-by-step explanation:

We know that the temperature in °F, of a cup of coffee t hours after it is set out to cool is given by the following equation:

$H(t)=70+120(\frac{1}{4})^t$

a) To find the temperature a t = 0 you need to replace the time in the equation:

$H(0)=70+120(\frac{1}{4})^0\\H(0)=70+120\cdot 1\\H(0) = 70+120\\H(0)=190 \:\°F$

b) To find the temperature after 1 hour you need to:

$H(1)=70+120(\frac{1}{4})^1\\H(1)=70+120(\frac{1}{4})\\H(1) = 70+30\\H(1)=100 \:\°F$

c) To find the temperature after 2 hours you need to:

$H(2)=70+120(\frac{1}{4})^2\\H(2)=70+120(\frac{1}{16})\\H(2) = 70+\frac{15}{2} \\H(2)=77.5 \:\°F$

d) To find the time to take the coffee to cool down $85 \:\°F$ , you need to:

$85 = 70+120(\frac{1}{4})^t\\70+120\left(\frac{1}{4}\right)^t=85\\70+120\left(\frac{1}{4}\right)^t-70=85-70\\120\left(\frac{1}{4}\right)^t=15\\\frac{120\left(\frac{1}{4}\right)^t}{120}=\frac{15}{120}\\\left(\frac{1}{4}\right)^t=\frac{1}{8}$

$\mathrm{If\:}f\left(x\right)=g\left(x\right)\mathrm{,\:then\:}\ln \left(f\left(x\right)\right)=\ln \left(g\left(x\right)\right)$

$\ln \left(\left(\frac{1}{4}\right)^t\right)=\ln \left(\frac{1}{8}\right)$

$\mathrm{Apply\:log\:rule}=\log _a\left(x^b\right)=b\cdot \log _a\left(x\right)$

$t\ln \left(\frac{1}{4}\right)=\ln \left(\frac{1}{8}\right)$

$t=\frac{\ln \left(\frac{1}{8}\right)}{\ln \left(\frac{1}{4}\right)}\\t=\frac{3}{2} = 1.5 \:hours$

e) To find the time to take the coffee to cool down $75 \:\°F$ , you need to:

$75=70+120\left(\frac{1}{4}\right)^t\\70+120\left(\frac{1}{4}\right)^t=75\\70+120\left(\frac{1}{4}\right)^t-70=75-70\\120\left(\frac{1}{4}\right)^t=5\\\left(\frac{1}{4}\right)^t=\frac{1}{24}$

$\ln \left(\left(\frac{1}{4}\right)^t\right)=\ln \left(\frac{1}{24}\right)\\t\ln \left(\frac{1}{4}\right)=\ln \left(\frac{1}{24}\right)\\t=\frac{\ln \left(24\right)}{2\ln \left(2\right)} \approx = 2.293 \:hours$

3 0

3 years ago

How many solutions does the system of equations have?

Marysya12 [62]

Step-by-step explanation:

A system of linear equations usually has a single solution, but sometimes it can have no solution (parallel lines) or infinite solutions (same line).

7 0

1 year ago

Read 2 more answers