Systems of Linear Equations Unit Test

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Question
Solve the system of equations.
6x−3y=−6

9x−3y=−18
(1 point)
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1 answer

To solve the system of equations:

  1. \(6x - 3y = -6\) (Equation 1)
  2. \(9x - 3y = -18\) (Equation 2)

We can start by rewriting both equations to see if they are equivalent or have a unique solution.

Let's simplify each equation.

From Equation 1: \[ 6x - 3y = -6 \] Divide the entire equation by 3: \[ 2x - y = -2 \quad \text{(Equation 1 simplified)} \]

From Equation 2: \[ 9x - 3y = -18 \] Divide the entire equation by 3: \[ 3x - y = -6 \quad \text{(Equation 2 simplified)} \]

Now, we can compare the two simplified equations:

  1. \(2x - y = -2\)
  2. \(3x - y = -6\)

Next, let's use the method of elimination. Subtract Equation 1 from Equation 2:

\[ (3x - y) - (2x - y) = -6 - (-2) \] This simplifies to: \[ 3x - 2x = -6 + 2 \] Which gives: \[ x = -4 \]

Now, substitute \(x = -4\) back into one of the original equations to find \(y\). We'll use Equation 1:

\[ 6(-4) - 3y = -6 \] This simplifies to: \[ -24 - 3y = -6 \] Adding 24 to both sides: \[ -3y = 18 \] Dividing by -3: \[ y = -6 \]

Thus, the solution to the system of equations is: \[ (x, y) = (-4, -6) \]

The final answer is: \[ \boxed{(-4, -6)} \]