-3 M squared + x 4 M cubed N squared over 2 m squared n old squared x 3 m n where m equals 4 + n equals -3

What are these two questions please help

Kay [80]

15 feet is what I came up with.

3 0

3 years ago

Can you simplify 3/r + 7/r+3

Nutka1998 [239]

Combine the fractions by finding a common denominator.
10r+9/r(r+3)

7 0

3 years ago

Kryptonite is a material found on the planet Krypton and has various effects, most importantly on Superman. The most common type

Rashid [163]

Answer:

The maximum amount of red kryptonite present is 33.27 g after 4.93 hours.

Step-by-step explanation:

dy/dt = y(1/t - k)

separating the variables, we have

dy/y = (1/t - k)dt

dy/y = dt/t - kdt

integrating both sides, we have

∫dy/y = ∫dt/t - ∫kdt

㏑y = ㏑t - kt + C

㏑y - ㏑t = -kt + C

㏑(y/t) = -kt + C

taking exponents of both sides, we have

$\frac{y}{t} = e^{-kt + C} \\\frac{y}{t} = e^{-kt}e^{C} \\\frac{y}{t} = Ae^{-kt} (A = e^{C})\\y = Ate^{-kt}$

when t = 1 hour, y = 15 grams. So,

$y = Ate^{-kt}\\15 = A(1)e^{-kX1}\\15 = Ae^{-k}$ (1)

when t = 3 hours, y = 30 grams. So,

$y = Ate^{-kt}\\30 = A(3)e^{-kX3}\\30 = 3Ae^{-3k}$ (2)

dividing (2) by (1), we have

$\frac{30}{15} = \frac{3Ae^{-3k}}{Ae^{-k}} \\2 = 3e^{-2k}\\\frac{2}{3} = e^{-2k}$

taking natural logarithm of both sides, we have

-2k = ㏑(2/3)

-2k = -0.4055

k = -0.4055/-2

k = 0.203

From (1)

$A = 15e^{k} \\A = 15e^{0.203} \\A = 15 X 1.225\\A = 18.36$

Substituting A and k into y, we have

$y = 18.36te^{-0.203t}$

The maximum value of y is obtained when dy/dt = 0

dy/dt = y(1/t - k) = 0

y(1/t - k) = 0

Since y ≠ 0, (1/t - k) = 0.

So, 1/t = k

t = 1/k

So, the maximum value of y is obtained when t = 1/k = 1/0.203 = 4.93 hours

$y = 18.36(1/0.203)e^{-0.203t}\\y = \frac{18.36}{0.203}e^{-0.203X1/0.203}\\y = 90.44e^{-1}\\y = 90.44 X 0.3679\\y = 33.27 g$

<u>So the maximum amount of red kryptonite present is 33.27 g after 4.93 hours.</u>

3 0

3 years ago

If Ashley is in the 85th percentile and the mean of her test scores is 180 with a standard deviation of 15, which of the followi

ioda

<span>B would be the most appropriate response for this. We don't need to worry about Ashley being in the 85th percentile, that is just extra information they have provided us. What we need to look at is her mean test score is 180, so that is the average score she normally gets on her tests, but then they say she has a standard deviation of 15 which means her scores are normally no lower than 165 and no higher than 195 because she normally doesn't deviate or change her score more than 15 points for her normal 180. So if you take 180 minus 15 you get 165 and if you take 180 plus 15 you get 195, therefore we can determine that the most appropriate answer would be between 165 and 195. The only option that fits in this category is B 185</span>

6 0

3 years ago

What is the definition of y=mx+b

Brut [27]

Answer:

In the equation of a straight line (when the equation is written as "y = mx + b"), the slope is the number "m" that is multiplied on the x, and "b" is the y-intercept (that is, the point where the line crosses the vertical y-axis).

Step-by-step explanation:

4 0

3 years ago

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