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
sweet-ann [11.9K]
3 years ago
12

The sum of two numbers is 9. And the sum of their reciprocals is 1/2.find the numbers

Mathematics
1 answer:
Musya8 [376]3 years ago
7 0
Set up a system of equations:

x + y = 9
1/x +1/y = 1/2

The easiest way to solve would be substitution.
x + y = 9 can be solved for y:

y = 9 - x

Then plug this into the second equation and solve for x:

1/x + 1/(9-x) = 1/2
(9-x) + x = x(9-x)/2
9 = (9x-x²)2
18 = 9x - x²
x² - 9x + 18 = 0
(x-6)(x-3) = 0
x = 6, 3

You can check your answer by plugging the two numbers back into both of the equations:

6 + 3 = 9
1/6 + 1/3 = 1/2

The two numbers are 6 and 3.
You might be interested in
Need help on algebra
vlada-n [284]
I can help you with algebra butttttttttt wheres the question?

5 0
3 years ago
Idk how to do this I’m stuck and don’t know what to do it’s due today can someone give me the answers
wel
A: When they were distributing the 2, they didn’t distribute it to the 5. The correct answer would be 6x + 10

B: They didn’t distribute the 3 to the -3. The answer should be 6x^2 - 9

C: They didn’t distribute the -3 to the -4. The correct answer should be -9x + 12

D: The -20 should be a positive 20 because -4 x -5= 20. The correct answer should be -16x + 20

E: The 12 should be a -12 because -2 x 6= -12. The correct answer should be -8x^2 -12

F: They didn’t distribute the -9 correctly. The correct answer should be -36x^3 + 45x -54


Hope this helps!

-Grace
7 0
3 years ago
Suppose that 30% of all students who have to buy a text for a particular course want a new copy (the successes!), whereas the ot
Softa [21]

Answer:

a. Mean = 4.5, Standard Deviation = 1.775

b. 0.0152

Step-by-step explanation:

Given

n = 15 purchasers

p = Success = 30%

p = 0.3

q =Failure = 70%

q = 0.7

a.

Mean = np

Mean = 15 * 0.3

Mean = 4.5

Standard Deviation = √Variance

Variance = npq

Variance = 15 * 0.3 * 0.7

Variance = 3.15

Standard Deviation = √3.15

Standard Deviation = 1.774823934929884

Standard Deviation = 1.775 ---------- Approximated

b.

The probability that the number who want new copies is more than two standard deviations away from the mean value

Standard Deviation = 1.775

Mean = 4.5

2 Standard Deviation and Mean = 2 * 1.775 + 4.5

= 3.55 + 4.5

= 8.05

P(X>8.05) = P(9) + P(10) +........+ P(15)

Using the binomial distribution

(p + q) ^ n where p = 0.3, q = 0.7 , n = 15

Expanding (p+q)^n where n = 15 and r > 8

We have

15C9 p^9 q^6 + 15C10 p^10 q^5 + 15C11 p^11 q⁴ + 15C12 p^12 q³ + 15C13 p^13 q² + 15C14 p^14 q + p^15

= 5005 (0.3)^9 (0.7)^6 + 3003 (0.3)^10 (0.7)^5 + 1365 (0.3)^11 (0.7)⁴ + 455 (0.3)^12 (0.7)³ + 105 (0.3)^14 (0.7)² + 15 (0.3)^14 (0.7) + 0.3^15

=0.015234

7 0
3 years ago
-5/6x = 20 2/3(x - 7) = -2 solve them and show your work! ASAP! I need this done fast!!
LenKa [72]

Answer:

x=-24 & x=4.

Step-by-step explanation:

-5/6x=20

x=20/(-5/6)

x=(20/1)(-6/5)=-120/5=-24

-------------------------------------

2/3(x-7)=-2

2/3x-14/3=-2

2/3x=-2+14/3

2/3x=-6/3+14/3

2/3x=8/3

x=(8/3)/(2/3)

x=(8/3)(3/2)=8/2=4

3 0
3 years ago
What is 175.42 rounded to the nearest tenth?
weqwewe [10]
175.4 because 4 is the tenth place and 2 would round down
4 0
3 years ago
Other questions:
  • Thomas is a designer for Hull Toys. He is married, earns $526 weekly, and claims no allowances. His gross pay to date this year
    10·1 answer
  • Please help me with this.
    9·1 answer
  • 35a+140-15a=21a+147 can u solve this I'm having some trouble
    7·2 answers
  • HELP PLS!!Given the following data calculate the correlation coefficient. Then describe the correlation based on the correlation
    13·2 answers
  • Write each phrase as an algebraic expression
    10·1 answer
  • According to one theory of learning, the number of items, w(t), that a person can learn after t hours of instruction is given by
    13·1 answer
  • A spinner numbered 1 to 6 is spun twice . what is the probability of getting a 3 on the first spin and an odd number on the seco
    13·1 answer
  • Fill this out pls lol
    6·2 answers
  • Which are the true statements?
    5·1 answer
  • Solve for the variable.<br> 6x-5=12
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!