Solve the system of equations

{ 3x +2y =15
{ 5x -4y=-8

The ________ method was used to solve the system.
Responses
A elimination
B substitution
C graphing

What was the solution to the system?
Responses
A (9/2, 2)
B (2, 9/2)

1 answer

To solve the given system of equations:

  1. \( 3x + 2y = 15 \) (Equation 1)
  2. \( 5x - 4y = -8 \) (Equation 2)

Let's use the elimination method to solve for \(x\) and \(y\).

First, we can multiply Equation 1 by 2 in order to align the \(y\) coefficients:

\[ 2(3x + 2y) = 2(15) \implies 6x + 4y = 30 \quad (Equation 3) \]

Now we have:

  • Equation 3: \( 6x + 4y = 30 \)
  • Equation 2: \( 5x - 4y = -8 \)

Next, we can add Equation 3 and Equation 2:

\[ (6x + 4y) + (5x - 4y) = 30 + (-8) \] \[ 6x + 4y + 5x - 4y = 30 - 8 \] \[ 11x = 22 \]

Now we solve for \(x\):

\[ x = \frac{22}{11} = 2 \]

Next, we substitute \(x = 2\) back into Equation 1 to find \(y\):

\[ 3(2) + 2y = 15 \] \[ 6 + 2y = 15 \] \[ 2y = 15 - 6 \] \[ 2y = 9 \] \[ y = \frac{9}{2} \]

The solution to the system of equations is \( (2, \frac{9}{2}) \).

Thus, the answers to the questions are:

  • The elimination method was used to solve the system. (Response A)
  • The solution to the system is \( (2, \frac{9}{2}) \). (Response B)