Solving with Elimination Practice

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Question
Solve the system of equations.
7x+3y=−25

−7x+9y=−47
(1 point)
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1 answer

To solve the system of equations using elimination, we have the following equations:

  1. \( 7x + 3y = -25 \)
  2. \( -7x + 9y = -47 \)

We can eliminate \( x \) by adding the two equations together since the coefficients of \( x \) are opposites:

\[ (7x + 3y) + (-7x + 9y) = -25 + (-47) \]

This simplifies to:

\[ (7x - 7x) + (3y + 9y) = -25 - 47 \]

\[ 0 + 12y = -72 \]

Dividing both sides by 12, we get:

\[ y = -6 \]

Now that we have the value of \( y \), we can substitute it back into one of the original equations to solve for \( x \). We'll use the first equation:

\[ 7x + 3(-6) = -25 \]

This simplifies to:

\[ 7x - 18 = -25 \]

Adding 18 to both sides:

\[ 7x = -25 + 18 \]

\[ 7x = -7 \]

Dividing both sides by 7, we get:

\[ x = -1 \]

Now we can express the solution as an ordered pair:

\[ (x, y) = (-1, -6) \]

Thus, the solution to the system of equations is:

\[ \boxed{(-1, -6)} \]