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4 years ago

2 7/8 as a decimal please answer this im in a test rn

Mathematics

1 answer:

Furkat [3]4 years ago

4 0

Hi there!

$2\frac{7}{8} = 2.875$

Hope this helped you!

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What is the y-intercept of this line? y = 3x + 4

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The y-intercept is 4 because it is the only number without a variable

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3 years ago

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4 3/4+2 5/6=how do I solve this problem

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A car is traveling down a highway at a constant speed, described by the equation d=65t, where d represents the distance, in mile

Alexxx [7]

Answer:

Step-by-step explanation:

We are given an equation d = 65 t, where d represents the distance, in miles, that the car travels at this speed in t hours.

We know distance, speed and time relation

d = s * t.

Where d represents the distance, that the car travels at this speed in t at the speed s.

If we compare that relation with the given equation, we can see s = 65.

So,

a) The 65 tell us speed of 65 miles per hour in this situation.

b) Second part seems to be incorrect. Please check it again.

c) We are given distance = 26 miles.

Plugging d= 26 in the given equation.

26 = 65 t

Dividing both sides by 65, we get

26/65 = t

t= 0.4 hours.

So, it takes 0.4 hours or 0.4 * 60 = 24 minutes o travel 26 miles at this speed.

6 0

3 years ago

Solve each equation by completing the square. If necessary, round to the nearest hundredth.

Ksenya-84 [330]

$1.)\\ \\ b^2+10b=75\\ \\ b^2+10b-75=0\\ \\\Delta = b^{2}-4ac = 10^{2}-4*1*(75)=100+300=400 \\ \\\sqrt{\Delta }=\sqrt{400}=20$

$b_{1}=\frac{-b-\sqrt{\Delta }}{2a} =\frac{-10-20}{2}=\frac{-30}{2}=-15\\ \\b_{2}=\frac{-b+\sqrt{\Delta }}{2a} =\frac{-10+20}{2}=\frac{10}{2}=5$

$2.)\\ \\ n^2-20n=-75\\ \\ n^2-20n+75=0\\ \\\Delta = b^{2}-4ac = (-20)^{2}-4*1*75=400-300=100 \\ \\\sqrt{\Delta }=\sqrt{100}=10$

$n_{1}=\frac{-b-\sqrt{\Delta }}{2a} =\frac{20-10}{2}=\frac{10}{2}=5\\ \\n_{2}=\frac{-b+\sqrt{\Delta }}{2a} \frac{20+10}{2}=\frac{30}{2}=15$

$3.)\\ \\t^2+8t-9=0\\ \\\Delta = b^{2}-4ac = 8^{2}-4*1* (-9)=64+36=100 \\ \\\sqrt{\Delta }=\sqrt{100}=10$

$t_{1}=\frac{-b-\sqrt{\Delta }}{2a} =\frac{-8-10}{2}=\frac{-18}{2}=-9\\ \\t_{2}=\frac{-b+\sqrt{\Delta }}{2a} \frac{-8+10}{2}=\frac{2}{2}=1$

$4.)\\ \\m^2-2m-8=0\\ \\\Delta = b^{2}-4ac = (-2)^{2}-4*1* (-8)=4+32=36\\ \\\sqrt{\Delta }=\sqrt{36}=6$

$m_{1}=\frac{-b-\sqrt{\Delta }}{2a} =\frac{2-6}{2}=\frac{-4}{2}=-2\\ \\m_{2}=\frac{-b+\sqrt{\Delta }}{2a}= \frac{2+6}{2}=\frac{8}{2}=4$

$5.)\\ \\ v^2+4v-2=0\\ \\\Delta = b^{2}-4ac = 4^{2}-4*1* (-2)=16+8=24\\ \\\sqrt{\Delta }=\sqrt{24}= \sqrt{4*6}=2\sqrt{6}$

$v_{1}=\frac{-b-\sqrt{\Delta }}{2a} =\frac{-4-2\sqrt{6}}{2}=\frac{2(-2-\sqrt{6}}{2}= -2-\sqrt{6}\approx -2-2,45\approx -4,45\\ \\v_{2}=\frac{-b+\sqrt{\Delta }}{2a}= \frac{-4+2\sqrt{6}}{2}=\frac{2(\sqrt{6}-2}{2}= \sqrt{6}-2 \approx 2,45-2\approx 0,45$

3 0

3 years ago

Let C(t) be the concentration of a drug in the bloodstream. As the body eliminates the drug, C(t) decreases at a rate that is pr

tia_tia [17]

Answer:

See explanation below

Step-by-step explanation:

In this case, let's answer this by parts:

<u>a) Concentration at time t when Co is concentration at t = 0:</u>

In this case, we will use the initial expression but without the 2, so:

C(t) = -kC

In this case, we want to know the concentration at time t so:

C'(t) = -kC(t) derivating:

dC/dt = -kC

dC/C = -kdt From here, we can do integrals so:

lnC = -kt + C₁ (1)

Now, it's time to replace t = 0 and C = C₀:

lnC₀ = -k(0) + C₁

lnC₀ = C₁ (2)

Replacing (2) in (1) we have:

lnC = -kt + lnC₀

lnC - lnC₀ = -kt

ln(C/C₀) = -kt

C/C₀ = e^(-kt)

C(t) = C₀ e^(-kt) (3)

This is the expression for C at given time t.

<u>2. time to eliminate 80% of the drug:</u>

With the first data, we need to calculate the value of k, which will be constant at any given time so:

C(t) = C₀ e^(-kt)

0.5C₀ = C₀ e^(-30k)

0.5 = e^(-30k)

ln(0.5) = -30k

k = 0.02310

Now with this value we can calculate the time to eliminate 80% of the drug or simply in other words, that we just have a remaining of 0.2C₀:

0.2C₀ = C₀ e^(-0.0231t)

ln(0.2) = -0.0231t

-ln(0.2) / 0.0231 = t

t = 69.67 h

This is the time to eliminate 80% of the drug

8 0

3 years ago