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
stiv31 [10]
3 years ago
5

5x+7y=31 2x+4y=16 Which of the following systems could be used to solve the given system of equations by the addition method? 10

x + 14y = 31 and -10x - 20y = 16 10x + 14y = 62 and 10x + 20y = 32 -10x - 14y = -62 and 10x + 20y = 80
Mathematics
1 answer:
Pani-rosa [81]3 years ago
3 0
Equation 1: 5x+7y=31
Equation 2: 2x+4y=16

We can either use the 'elimination' method or the 'substitution' method to solve this simultaneous equation.

In some cases one method is easier to use than the other. For this one, it would be easier to use the elimination method

We need to eliminate either the 'x' or the 'y' to begin with. Say we want to eliminate the 'x' terms, then the next step is to make the constant the same

Equation 1: the constant of 'x' is 5
Equation 2: the constant of 'x' is 2

To make the two constants the same, think of common multiple. The lowest common multiple for 5 and 2 is 10

Equation 1:  Multiply all terms by 2 to achieve 10x
Equation 2: Multiply all terms by 5 to achieve 10x

Equation 1: 10x+14y=62
Equation 2: 10x+20y=80

Once the constant of 'x' is the same, then we can start the elimination process. Since our aim is to eliminate, one of the 'x' need to be in negative form. We can either multiply Equation 1 or Equation 2 by (-1)

Equation 1: -10x - 14y = -62
Equation 2: 10x + 20y = 80

Hence the correct answer is: Third option




You might be interested in
If a cube with the length of the side of 4 cm is cut into smaller cubes with the length of the side of 1 cm, then what is the pe
ValentinkaMS [17]

Answer:

300 %

Step-by-step explanation:

Length of the larger cube =4 cm

So volume V=side^3=4^3=64cm^3

Length of the smaller cube = 1 cm

Volume of the smaller cube V=side^3=1^3=1cm^3

So total number of smaller cube =\frac{64}{1}=64

Surface area of the larger cube A=6\times side^2=6\times 4^2=144cm^2

Surface area of the 64 smaller cube A=64\times 6\times side^2=64\times 6\times 1^2=384cm^2

So percentage increase in surface area =\frac{384-96}{96}\times 100=300 %

6 0
3 years ago
So I was doing a hooda math escape game, and forgot how to do these. Can you help me?
Alika [10]

to find the radius you divide the circumference by 2pi

area is pi times radius to the 2nd power

5 0
3 years ago
Read 2 more answers
33 1/3% of 75<br><br>plz help​
Paraphin [41]

The answer is 25

x 33 1/3% = 75

75 / 33 1/3

0.3333

(75)(0.333) =  25

24.9999999 rounds to 25

Hope this helps, have a BLESSED day! :-)

6 0
3 years ago
The perimeter of a triangle is 47 feet. One side of the triangle is one foot longer than the second side. The third side is four
Ugo [173]

Answer:

The lengths of all three sides (in feet) are = 15, 14, and 18 feet

Step-by-step explanation:

Perimeter of Triangle = 47ft

Let the one side be 'x'

<em>Side 1 = x</em>

One side of the triangle is one foot longer than the second side

<em>Side 2 = x - 1</em>

<em>The third side is four feet longer than the second side</em>

<em>Side 3 = (x - 1) + 4</em>

<em />

<em>Perimeter = sum of all sides</em>

<em>47 = x + (x - 1) + (x - 1) + 4</em>

<em>47 = x + x - 1 + x - 1 + 4</em>

<em>47 = 3x + 2</em>

<em>47 - 2 = 3x</em>

45 = 3x

<u>x = 15</u>

substitute for x in each of the sides

<em>Side 1 = x                   => </em><em>15 feet</em>

<em>Side 2 = x - 1              => 15 - 1 = </em><em>14 feet</em>

<em>Side 3 = (x - 1) + 4      => 14 + 4 = </em><em>18 feet</em>

6 0
3 years ago
Read 2 more answers
How long can late payments stay on your credit report?
ratelena [41]
The exception is if you are 60 days<span> late often which will certainly hurt your scores. Otherwise, one late payment should not cause long term damage. </span>90 days<span>late: This record will damage your credit scores significantly for up to </span>seven years<span>.</span>
5 0
2 years ago
Other questions:
  • Find the area of a regular nonagon with a side length of 9 and an apothem of 16
    7·1 answer
  • Two cities are 847 miles apart. Convert this distance to kilometers. State your answer to the nearest tenth of a kilometer
    6·2 answers
  • Three to the second power times eight to the fourth power
    13·1 answer
  • Which expression is equivalent to 2x x2 3x 5x2 - 10x?
    15·1 answer
  • Two researchers conducted a study in which two groups of students were asked to answer 42 trivia questions from a board game. Th
    9·1 answer
  • Jack asked 100 students to choose their favorite subject from among world cultures, math, and art. He found that 22 students cho
    8·1 answer
  • Find f'(x) if f(x)=3squareroot(x+2)<br>using the definition of the derivative!
    11·1 answer
  • 5. Cost to store: $65<br> Markup: ?<br> Selling price: $91
    15·1 answer
  • Please help me!
    8·2 answers
  • Simplify 4 to the 2nd power • 4 to the 8th power
    13·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!