Use the substitution method to solve the system 2x + 3y = 4, -4x - 6y = -8

1 answer

To solve the system of equations using the substitution method, we first have the two equations:

  1. \( 2x + 3y = 4 \)
  2. \( -4x - 6y = -8 \)

Notice that the second equation can be simplified. Divide every term in the second equation by -2:

\[ -4x - 6y = -8 \implies 2x + 3y = 4 \]

Now our system looks like this:

  1. \( 2x + 3y = 4 \)
  2. \( 2x + 3y = 4 \)

Both equations are actually the same line. This means the system has infinitely many solutions along the line represented by the equation \( 2x + 3y = 4 \).

To express the solutions parametrically, we can solve for \( y \) in terms of \( x \):

\[ 3y = 4 - 2x \] \[ y = \frac{4 - 2x}{3} \]

Thus, we have:

\[ \text{Solutions: } (x, y) = \left( x, \frac{4 - 2x}{3} \right) \quad \text{for any real number } x. \]

In conclusion, the solution set to the system of equations is infinite, represented as:

\[ { (x, \frac{4 - 2x}{3}) : x \in \mathbb{R} } \]