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3 years ago

If q=2. Evaluate (34+18*q)-(5q+7)

Mathematics

2 answers:

Viefleur [7K]3 years ago

7 0

Answer:

The value of the expression at q = 2 is 53.

Step-by-step explanation:

Consider the provided information.

The provided expression is (34+18q)-(5q+7).

Now substitute the value of q = 2 in the above expression.

$(34+18q)-(5q+7)$

$(34+18(2))-(5(2)+7)$

$(34+36)-(10+7)$

$(70)-(17)$

$70-17$

$53$

Hence, the value of the expression at q = 2 is 53.

stiv31 [10]3 years ago

3 0

Q= 27/31
34+18*2= 34+38q
34+38q-5q7
33q + 41

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141.1933-67.53 =<br> (Divided, not minus)

Sphinxa [80]

Answer: I think its 2.09

Step-by-step explanation:

But i'm not sure.

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3 years ago

Initially 100 milligrams of a radioactive substance was present. After 6 hours the mass had decreased by 3%. If the rate of deca

Hitman42 [59]

Answer:

The half-life of the radioactive substance is 135.9 hours.

Step-by-step explanation:

The rate of decay is proportional to the amount of the substance present at time t

This means that the amount of the substance can be modeled by the following differential equation:

$\frac{dQ}{dt} = -rt$

Which has the following solution:

$Q(t) = Q(0)e^{-rt}$

In which Q(t) is the amount after t hours, Q(0) is the initial amount and r is the decay rate.

After 6 hours the mass had decreased by 3%.

This means that $Q(6) = (1-0.03)Q(0) = 0.97Q(0)$ . We use this to find r.

$Q(t) = Q(0)e^{-rt}$

$0.97Q(0) = Q(0)e^{-6r}$

$e^{-6r} = 0.97$

$\ln{e^{-6r}} = \ln{0.97}$

$-6r = \ln{0.97}$

$r = -\frac{\ln{0.97}}{6}$

$r = 0.0051$

$Q(t) = Q(0)e^{-0.0051t}$

Determine the half-life of the radioactive substance.

This is t for which Q(t) = 0.5Q(0). So

$Q(t) = Q(0)e^{-0.0051t}$

$0.5Q(0) = Q(0)e^{-0.0051t}$

$e^{-0.0051t} = 0.5$

$\ln{e^{-0.0051t}} = \ln{0.5}$

$-0.0051t = \ln{0.5}$

$t = -\frac{\ln{0.5}}{0.0051}$

$t = 135.9$

The half-life of the radioactive substance is 135.9 hours.

6 0

3 years ago

triangle RSt is similar to triangle xyz with rs= 3 inches and xy= 2 inches. Of the area of triangle RST is 27 in^2, determine an

Luden [163]

Answer: The area of triangle ΔXYZ is 12 square inches.

Step-by-step explanation:

Since we have given that

RS = 3 inches

XY = 2 inches

Area of ΔRST = 27 in²

Since ΔRST is similar to ΔXYZ.

So, using the "Area similarity theorem":

$\dfrac{\Delta RST}{\Delta XYZ}=\dfrac{RS^2}{XY^2}\\\\\dfrac{27}{\Delta XYZ}=\dfrac{3^2}{2^2}\\\\\dfrac{27}{\Delta XYZ}=\dfrac{9}{4}\\\\\Delta XYZ=3\times 4=12\ in^2$

Hence, the area of triangle ΔXYZ is 12 square inches.

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3 years ago

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almond37 [142]

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3 years ago

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erma4kov [3.2K]

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3 years ago