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
irga5000 [103]
3 years ago
14

If 5y = 6x + 16 and 9x = 7y-20, what is the value of 3x - 2y?

Mathematics
2 answers:
Law Incorporation [45]3 years ago
5 0

The value of 3x-2y is -4. From the equation 5y=6x=16 and 9x=7y-20 the values of (x,y) is (4,8).

Step-by-step explanation:

        The given equations are,

                 5y=6x+16.......................(1)

                 9x=7y-20......................(2)

                3x-2y...............................(3)

Step:1

    Modify the equations (1) and (2) in (x+y=constant) format,

                6x-5y=-16.....................(4)

                9x-7y=-20....................(5)

Step:2

     Equation (4) is multiplied by 7     ( ∵ 7×Eqn(4))

                42x-35y=-112..............(6)

Step:3

     Equation (5) is multiplied by 5     (∵ 5×Eqn(5))

               45x-35y=-100.............(7)

Step:4

    Subtracting Equation (6) and (7)

               42x-35y=-112

              45x-35y=-100

    ( - )

     (42x-45x)+(35y-35y)=(100-112)

     (-3x)+(0)=(-12)

    x=4

Step:5

    Substitute X value in Equation (1),

             5y=6x+16...................(1)

     where, x=4,

             5y= (6×4)+16

             5y=40

            y= 8

Step: 6

      Check for solution, substitute x and y values in equation (2).

                9x=7y-20.......................(2)

               (9×4)=(7×8)-20

              36=36

Step:7

      From given, 3x-2y

      where, X=4 and y=8

              3x-2y = (3×4)-(2×8)

                        = 12-16

            3x-2y = -4

Result:

      The value for 3x-2y is -4. The values of (x,y) are (4,8).

   

Scrat [10]3 years ago
5 0

Answer:

-4

Step-by-step explanation:

When you graph the system, the 2 lines intersect at the point (4,8). Therefore, the x is 4 and the y is 8. If you plug in 4 and 8 into 3x-2y, you get 3(4)-2(8)=12-16=-4.

You might be interested in
What is the density of the oak board, it's 5.5 inches wide, 1.5 inches thick , 3 feet long and weighs 8.05 lbs? Please show work
laiz [17]

Answer:

37 - 56 lb / ft3

0.6 - 0.9 103 kg / m3

Step-by-step explanation:

The density or hardness of wood varies by species, and the value is necessary to approximate the weight of lumber by volume. In this table, the density of different species of wood is expressed as weight in pounds per cubic foot and kilograms per cubic meter. The density will vary based on the moisture content of the wood.

8 0
3 years ago
"Large Sample Proportion Problem. Surveys were conducted in multiple countries and respondents were asked if they felt political
melomori [17]

Answer: 0.0158

Step-by-step explanation:

Given : The data for the United States is that out of 1,000 sampled, 470 indicated yes, they felt political news was reported fairly.

According to the given information we have,

Sample size : n= 1000

Sample proportion: \hat{p}=\dfrac{470}{1000}=0.47

The standard error for proportion is given by :-

S.E.=\sqrt{\dfrac{\hat{p}(1-\hat{p})}{n}}

S.E.=\sqrt{\dfrac{0.47(1-0.47)}{1000}}

S.E.=\sqrt{0.0002491}

S.E.=0.0157829021412\approx0.0158

[Rounded to the nearest four decimal places.]

Hence, the standard error for the confidence interval = 0.0158

6 0
3 years ago
HELPPPP
krek1111 [17]

Answer:

12.60

Step-by-step explanation:

To find the tip, take the amount of the bill and multiply by 30%

42 * 30%

Change to decimal form

42 * .30

12.6

3 0
3 years ago
Read 2 more answers
Please help me with this :)
Paul [167]
Just 7 would be the answer
4 0
3 years ago
Read 2 more answers
Zack bought a coat for $69.78. He paid with a $100 bill and received $26.73 in change.How Much was the sales tax? Show your work
Sindrei [870]
69.78+26.73-100 just use your calculator and you will out and that a hint
7 0
3 years ago
Other questions:
  • A cookie recipe that yields 48 cookies calls for 2 cups of flour a different cookie recipe that yields 60 cookies call for 3 cup
    7·1 answer
  • 8.) solve the absolute value equation |2n+15| = 1. one solution is n = -7. what is the other solution?
    8·1 answer
  • An item costs $320 before tax, and the sales tax is $22.40 . Find the sales tax rate. Write your answer as a percentage.
    15·1 answer
  • How you make a Ten with 26+5
    13·1 answer
  • The siding of a house is 2250 square feet. The siding needs two coats of paint. One quart costs $18 and covers 80 square feet. O
    14·1 answer
  • The half-life of a radioactive isotope is the time it takes for a quantity of the isotope to be reduced to half its initial mass
    8·1 answer
  • What is y in 15=-7.5x^2+86x+702
    12·1 answer
  • Please help <br><br> A 35<br> B 62<br> C 25<br> D 40
    14·2 answers
  • 2c + -2 = -6<br> what isthe answer
    8·1 answer
  • Write the equation of the circle graphed below
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!