1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Mademuasel [1]
3 years ago
14

Which equation is true for the value a = 7?

Mathematics
2 answers:
professor190 [17]3 years ago
7 0
THE first option is correct
liraira [26]3 years ago
5 0
Answers is A:
a +2a-6=15
3a=21
a=7
You might be interested in
938 divided by 7, pls give the solution too​
stellarik [79]

Answer:

134

Step-by-step explanation:

938÷7=134

8 0
2 years ago
Read 2 more answers
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
Whole-wheat bread costs $2.06/lb. How much would 3.8 lb of whole-wheat bread cost?
Xelga [282]
Whole-wheat bread = $2.06/lb

We need the cost of 3.8 lbs of whole-wheat bread.

So, we simply need to multiply the cost with the amount needed.

(cost per pound) × (amount of bread)

($2.06) × (3.8)

Simplify.

$7.828

Round to the nearest tenths.

$7.83

So, 3.8 pounds of whole wheat bread costs $7.83

~Hope I helped!~


7 0
3 years ago
Read 2 more answers
How many cups are in 25 gallons
dmitriy555 [2]
There are 400 cups in 25 Gallons !!!
8 0
2 years ago
Read 2 more answers
When the center of Earth is 3.8 × 105 kilometers from the center of the moon, the force of gravity between Earth and the moon is
kow [346]
I think the answer to you question is 35 i might be wrong tho but it may work.
7 0
3 years ago
Other questions:
  • Brad is putting an eight foot diameter circular garden
    10·1 answer
  • HELP ME HELP ME AAAAAAAAAAAAAAAAAAA HELP
    8·1 answer
  • Vertical angles must:Check all that apply. A.be congruent. B.be adjacent. C.have the same vertex. D.be obtuse.
    10·1 answer
  • What does 21 over 8 equals
    12·1 answer
  • What is 4 equal expressions to 4(2x^2+16)
    14·1 answer
  • PLEASE HELP ASAP AND SHOW YOUR WORK
    6·1 answer
  • A cd has 5% chance of being a smash hit an profiting $5.2 million a 50% chance of being a modest success and profiting $0.9 mill
    6·1 answer
  • I = $54, P = $800, r = 4.5%, What is the time
    5·1 answer
  • 5. For which equation is the ordered pair (-3,4) a solation?
    13·2 answers
  • Evaluate (−3a + 4b)32c − 1 when a = 4, b = 2, and c = 3. <br> Plz Help Its a quiz
    5·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!