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
Darina [25.2K]
2 years ago
14

Use elimination to find the solution to the system of equations.

Mathematics
2 answers:
hammer [34]2 years ago
8 0

Answer:  option B.

Step-by-step explanation:

You can apply the elimination method:

- Multiply the first equation by -7 and the second equation by 3.

- Add both equations to cancel out the variable y.

- Solve for x

\left \{ {{(-7)9x+3y=(-39)(-7)} \atop {(3)(4x+7y)=(-57)(3)}} \right.\\\\\left \{ {{-63x-21y=273} \atop {12x+21y=-171}} \right.\\-------\\-51x=102\\x=-2

- Substitute x=-2 into any of the original equations ans solve for y. Then:

9(-2)+3y=-39\\-18+3y=-39\\3y=-21\\y=-7

Aleksandr [31]2 years ago
7 0
<h2>Hello!</h2>

The answer is:

B.

x=-2\\y=-7

<h2>Why?</h2>

Solving the system of equations by elimination, we have:

\left \{ {{9x+3y=-39} \atop {4x+7y=-57}} \right.

Then, multiplying the second equation by -\frac{9}{4}

So,

\left \{ {{9x+3y=-39} \atop {4x*(-\frac{9}{4}) +7y*(-\frac{9}{4}) =-57*(-\frac{9}{4})}} \right\\\\\left \{ {{9x+3y=-39} \atop {-9x-\frac{63}{4}y=\frac{513}{4} }} \right\\\\-\frac{51}{4}y=\frac{357}{4}\\\\y=\frac{357}{4}*(-\frac{4}{51})=-\frac{1428}{204}=-7

Then, substituting y=-7 into the first equation (also, we could substitute it into the first equation) we have:

9x+3(-7)=-39\\9x-21=-39\\9x=-39+21\\9x=-18\\x=\frac{-18}{9}=-2

So, the solutions for the system of equations are:

x=-2\\y=-7

Have a nice day!

You might be interested in
HELP ME PLEASE
charle [14.2K]
540 cell phones. 1800 divided by 80 is 22.5, and 22.5 times 24 is 540. (but im not like 100% sure so good luck)
5 0
3 years ago
1.) What is the domain and range of the function in the graph?
olga_2 [115]

Answer:

Domain → (-∞, ∞)

Range → (-2, ∞)

Step-by-step explanation:

1). Domain of a function is defined by the input values (set of x-values) and Range of the function is defined by the output values (set of y-values).

From the graph attached,

Function is defined for all real values of x.

Therefore, domain of the function will be (-∞, ∞).

On y-axis values of the function vary from -2 (excluding 2) to positive infinity.

Therefore, range of the function will be (-2, ∞).

2). Average rate of change of a function in the interval (a, b) is defined by,

Average rate of change = \frac{f(b)-f(a)}{b-a}

By using this expression we can find the average rate of change in the given interval.

Please give the correct interval for which the average rate of change is to be calculated.

8 0
2 years ago
Which represents a quadratic function?
stiks02 [169]
F(x)=x2 + 2x - 5 represents a quadratic function
6 0
3 years ago
Evaluate 5c+cd when c =15 and d = 15
kirill [66]
5(15)+(15)(15)=75+225
=300
5 0
3 years ago
Read 2 more answers
How many squares are in the 20th case
pentagon [3]

Answer:

total 20 squares in matrix of size 4×3

Step-by-step explanation:

in square of size 1×1

six squares of size 2×2

2 squares of size 3×3

3 0
3 years ago
Other questions:
  • Mai conducted an experiment by flipping a fair coin 200 times. The coin landed heads up 110 times. Which statement about the
    14·2 answers
  • A regulation baseball field measures 90 feet between each base.What is the distance around the bases in meters?
    9·1 answer
  • What is the length of the altitude of the equilateral triangle below? Thank you! &lt;3
    14·2 answers
  • Please help, thanks!
    13·1 answer
  • Write an equation to model the following situation.
    14·2 answers
  • Find the slope of the line 6x – 2y = 6 (hint: find 2 points; then use the slope formula)
    8·1 answer
  • Is the answer 30% ??
    8·2 answers
  • Find the exact length of the third side .
    5·1 answer
  • A 500 g bag of rice costs $0.64.A 2 kg bag of the same rice costs $2.65.
    14·1 answer
  • On a coordinate plane, triangle A B C has points (negative 1, negative 1), (negative 2, negative 1) and (negative 2, negative 4)
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!