All categories

2 years ago

If d-6c=4 and 2d-9c=20, find the value of d/c

Mathematics

1 answer:

mash [69]2 years ago

3 0

Answer:

Step-by-step explanation:

You get the value of c and d as follow

c=4

d=28

now,

d/c=28/4=7

so,

the value of d/c here is 7

You might be interested in

How many fractions are equalavent to 4/5.

Alexeev081 [22]

The list of equal fractions could be very long, but here are a few that are equal to 4/5.

4*2 = 8
5*2 = 10

8/10 = 4/5
64/80 = 4/5
16/20 = 4/5

3 0

3 years ago

What is the factored form of -7y-y^2=0

Sveta_85 [38]

Factor out like terms
-y(7+y)=0

4 0

3 years ago

You purchase a stereo system for $830. The value of the stereo system decreases 13% each year. a. Write an exponential decay mod

lorasvet [3.4K]

Answer:

a. $y=830*(0.87)^x$

b. The value of stereo system after 2 years will be $628.23.

c. After approximately 4.98 years the stereo will be worth half the original value.

Step-by-step explanation:

Let x be the number of years.

We have been given that you purchased a stereo system for $830. The value of the stereo system decreases 13% each year.

a. Since we know that an exponential function is in form: $y=a*b^x$ , where,

a = Initial value,

b = For decay b is in form (1-r), where r is rate in decimal form.

Let us convert our given rate in decimal form.

$13\%=\frac{13}{100}=0.13$

Upon substituting our given values in exponential decay function we will get

$y=830*(1-0.13)^x$

$y=830*(0.87)^x$

Therefore, the exponential model $y=830*(0.87)^x$ represents the value of the stereo system in terms of the number of years since the purchase.

b. To find the value of stereo system after 2 years we will substitute x=2 in our model.

$y=830*(0.87)^2$

$y=830*0.7569$

$y=628.227\approx 628.23$

Therefore, the value of stereo system after 2 years will be $628.23.

c. The half of the original price will be $\frac{830}{2}=415$ .

Let us substitute y=415 in our model to find the time it will take the stereo to be worth half the original value.

$415=830*(0.87)^x$

Upon dividing both sides of our equation by 830 we will get,

$\frac{415}{830}=\frac{830*(0.87)^x}{830}$

$0.5=0.87^x$

Let us take natural log of both sides of our equation.

$ln(0.5)=ln(0.87^x)$

Using natural log property $ln(a^b)=b*ln(a)$ we will get,

$ln(0.5)=x*ln(0.87)$

$\frac{ln(0.5)}{ln(0.87)}=\frac{x*ln(0.87)}{ln(0.87)}$

$\frac{ln(0.5)}{ln(0.87)}=x$

$\frac{-0.6931471805599}{-0.139262067}=x$

$x=4.977286\approx 4.98$

Therefore, after approximately 4.98 years the stereo will be worth half the original value.

5 0

3 years ago

Need help ASAP! Which is the simplified form of the expression StartFraction (6 Superscript negative 4 Baseline) Superscript neg

Gelneren [198K]

Answer: D. $6^{30}$

Step-by-step explanation:

Using exponent rules an exponent to the power of a number will multiply by each other.

So the -4 and -9 will multiply.

The 6 in the numerator will now have a positive exponent of 36.

$\frac{6^{36}}{6^6}$

Now we can divide and when we do so the exponents will subtract from each other.

So 36 - 6 = 30

And the base of 6 does not change.

The simplified form is $6^{30}$

5 0

3 years ago

Read 2 more answers

What is the slope of a line that passes through the points (2,5) and (4,9)

ahrayia [7]

Answer:

Step-by-step explanation:

slope = difference of y/ difference of x

m = (9-5) / (4-2) = 4/2 = 2

8 0

3 years ago