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
marin [14]
3 years ago
9

Solve the system using elimination. 2x + 18y = -9 4x + 18y = -27

Mathematics
1 answer:
Elan Coil [88]3 years ago
4 0

First, let's cancel out the x by multiplying 2x + 18y = -9 by -2.

-2 ( 2x + 18y = -9) = -4x -36y = 18

Then, we combine the two equations.

-4x + 4x = 0

18y - 36y = -18y

-27 + 18 = -9

Our new equation is -18y = -9.

Now, divide both sides by -18.

-18y / -18 = y

-9/ -18 = 1/2

y = 1/2

We can plug in a value for y since y = 1/2 now.

Let's use 2x + 18y = -9

Plug in y.

2x + 18(1/2) = -9

2x + 9 = -9

Then, subtract 9 from both sides.

2x = -18

Divide by 2.

2x/2 = x

-18/2 = -9

x = -9

Lastly, we can plug in both x and y values to see it works.

2(-9) + 18(1/2) = -9

-18 + 9 = -9

Therefore, the values of x and y does work.

x = -9

y = 1/2

You might be interested in
Charlie runs at a speed of 3 yards per second.about how many miles does Charlie run
crimeas [40]
I think since he runs 3 yards per hour per second their are 60 seconds in a minute so 60 times  equals 180 yards per second
5 0
3 years ago
The solution to 4.2x = 19.32 is x = ___. (3 points)
trasher [3.6K]

Answer:

4.6

Step-by-step explanation:


3 0
2 years ago
Read 2 more answers
Help please! :)<br>Question in picture
sergey [27]

Answer:

70km per hour is the rate of change



6 0
3 years ago
Find integrate (1/(xsqrt(1+(lnx)^2)),1,e,x) ...?
prohojiy [21]
Note that x² + 2x + 3 = x² + x + 3 + x. So your integrand can be written as 

<span>(x² + x + 3 + x)/(x² + x + 3) = 1 + x/(x² + x + 3). </span>

<span>Next, complete the square. </span>

<span>x² + x + 3 = x² + x + 1/4 + 11/4 = (x + 1/2)² + (√(11)/2)² </span>

<span>Also, for the x in the numerator </span>

<span>x = x + 1/2 - 1/2. </span>

<span>So </span>

<span>(x² + 2x + 3)/(x² + x + 3) = 1 + (x + 1/2)/[(x + 1/2)² + (√(11)/2)²] - 1/2/[(x + 1/2)² + (√(11)/2)²]. </span>

<span>Integrate term by term to get </span>

<span>∫ (x² + 2x + 3)/(x² + x + 3) dx = x + (1/2) ln(x² + x + 3) - (1/√(11)) arctan(2(x + 1/2)/√(11)) + C </span>

<span>b) Use the fact that ln(x) = 2 ln√(x). Then put u = √(x), du = 1/[2√(x)] dx. </span>

<span>∫ ln(x)/√(x) dx = 4 ∫ ln u du = 4 u ln(u) - u + C = 4√(x) ln√(x) - √(x) + C </span>

<span>= 2 √(x) ln(x) - √(x) + C. </span>

<span>c) There are different approaches to this. One is to multiply and divide by e^x, then use u = e^x. </span>

<span>∫ 1/(e^(-x) + e^x) dx = ∫ e^x/(1 + e^(2x)) dx = ∫ du/(1 + u²) = arctan(u) + C </span>

<span>= arctan(e^x) + C.</span>
4 0
3 years ago
Sandy mixed together 9 gallons of one brand of juice and 8 gallons of a second brand of juice, which contains 48 percent real fr
Gekata [30.6K]

Answer:

14 %   pure juice comes from  first brand

Step-by-step explanation:

Mixture:

17 gal 30% contains:  17x 30% = 5.10 gal pure juice

 Second brand:

8 gal 48% contains:  8x40% =  3.84   gal pure juice

5.10 − 3.84 = 1.26   gal

1.26   gal is  coming  from 9 gal of first  brand

The percentage of first brand  is:

(1.26/9) x100  =  14 %   pure juice.

8 0
2 years ago
Other questions:
  • the radius of a gold atom is 1.35 angstroms. how many gold atoms would it take to line up a span of 8.5 mm?
    6·2 answers
  • I need help answering this please
    11·2 answers
  • Given 7x/2 &lt;5 find the soloution set
    6·1 answer
  • The sales price of a pair of pants is 65% of the regular price of $25. How much do you save by buying the pants on sale
    8·1 answer
  • Please help me with the Math. Thx in advance! <br> Number's 8-11. THANK YOU!
    9·2 answers
  • Fiona rolls a fair dice 192 times.<br> How many times would Fiona expect to roll a three?
    8·2 answers
  • Tom and Martha are making punch for a party. The proportions given in the recipe are 2 parts of lemonade to 1 part each of pinea
    13·1 answer
  • What is the angle of elevation of the sun when a 47 ​-ft mast casts 33ft​ shadow?
    9·1 answer
  • List all possible correct answers that complete the following statement.
    7·1 answer
  • 9 and 1/9 subtracted by 1 and 4/5
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!