Qwerty1956
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Please help. 10 points and brainliest.
Three times a number, x, plus four times a number, y, equals 81. Two times x minus four times y equals -46. Find the numbers by setting up a system of linear equations and solving the system using the elimination method.
x = 7, y = 15
x = 11, y = 9
x = 12, y= 11
x = -11, y = 13

Respuesta :

22stolc

Answer:

x = 7, y = 15

Step-by-step explanation:

3x + 4y = 81

2x - 4y = -46      Add together both equations

5x = 35              Divide both sides by 5

x = 7      

Plug this into the first equation

3x + 4y = 81

3(7) + 4y = 81       Multiply

21 + 4y = 81

-21          -21         Subtract 21 from both sides

4y = 60                Divide both sides by 4

y = 15

WeatheringWithYou

Answer: x = 7, y = 15

Step-by-step explanation:

First, set up the system of equations. You are given two statements which must be true in order to find the system.

First equation: Three times a number, x, plus four times a number, y, equals 81.

3x + 4y = 81

Second equation: Two times x minus four times y equals -46.

2x - 4y = -46

You can use the elimination method to solve for the variable x.

This method involves adding two equations together in order to remove one of the variables from the equation. The equations given are already prepared for the final step of elimination:

[tex]3x + 4y = 81\\2x - 4y = -46\\\\(3x + 2x) + (4y - 4y) = (81 - 46)\\5x = 35\\x = 7\\\\[/tex]

The correct choice is the first choice given: x = 7, y = 15. No other answer choices given have x = 7.

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