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Use the linear combination method to solve the system of equations. Justify each step of your solution. If steps are not explained, you will not receive credit for that step.
-3x - 7y = -28
2x + 3y = 7

Respuesta :

xdploper

Answer:

y=7

x=-7

Step-by-step explanation:

2(-3x - 7y )= 2(-28)

3(2x+ 3y)=3(7)

-6x - 14y = -56

6x + 9y = 21

Add the two equations

-1(0x - 5y)= -1(- 35)

5y = 35

Divide both sides by 5

y=7

Substitution

6x + 9(7) = 21

6x + 63 = 21

Subtract 63 from both sides

6x = -42

Divide both sides by 6

x= - 7

Answer:

Step-by-step explanation:

The given system of equations is expressed as

-3x - 7y = -28 - - - - - - - - - - - - 1

2x + 3y = 7 - - - - - - - - - - - - - - 2

We would eliminate x by multiplying equation 1 by 2 and equation 2 by 3. It becomes

- 6x - 14y = - 56- - - - - - - - - - - 3

6x + 9y = 21 - - - - - - - - - - - 4

Adding equation 3 to equation 4, it becomes

- 5y = - 35

Dividing the left hand side and the right hand side of the equation by - 5, it becomes

- 5y/- 5 = - 35/- 5

y = 7

Substituting y = 7 into equation 2, it becomes

2x + 3 × 7 = 7

2x + 21 = 7

Subtracting 21 from the left hand side and the right hand side of the equation, it becomes

2x + 21 - 21 = 7 - 21

2x = - 14

Dividing the left hand side and the right hand side of the equation by 2, it becomes

2x/2 = - 14/2

x = - 7

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