Solve the system of equations.

–9x+y=12

2x+4y= −28
(1 point)

1 answer

To solve the system of equations:

  1. \(-9x + y = 12\) \
  2. \(2x + 4y = -28\)

We can use either substitution or elimination. Let's use substitution.

From equation (1), we can express \(y\) in terms of \(x\):

\[ y = 12 + 9x \]

Now, we can substitute this expression for \(y\) into equation (2):

\[ 2x + 4(12 + 9x) = -28 \]

Now, distribute the \(4\):

\[ 2x + 48 + 36x = -28 \]

Combine like terms:

\[ 38x + 48 = -28 \]

Now, subtract \(48\) from both sides:

\[ 38x = -28 - 48 \] \[ 38x = -76 \]

Now, divide by \(38\):

\[ x = \frac{-76}{38} = \frac{-38}{19} = -2 \]

Now that we have \(x\), we can substitute it back into the expression we found for \(y\):

\[ y = 12 + 9(-2) \] \[ y = 12 - 18 \] \[ y = -6 \]

Thus, the solution to the system of equations is:

\[ (x, y) = (-2, -6) \]

To verify, plug \(x = -2\) and \(y = -6\) back into the original equations.

For equation (1):

\[ -9(-2) + (-6) = 18 - 6 = 12 \quad \text{(True)} \]

For equation (2):

\[ 2(-2) + 4(-6) = -4 - 24 = -28 \quad \text{(True)} \]

Both equations are satisfied, so the solution is confirmed:

\[ \boxed{(-2, -6)} \]