Which statements about this system of equations are true? Check all that apply

2 x minus 7 y = negative 13. Negative 2 x + 11 y = 1.
The x-variable will be eliminated when adding the system of equations.
The y-variable will be eliminated when adding the system of equations.
The sum of the system of equations is 4 y = negative 12.
x = 17
y = negative 3
There are infinitely many solutions to the system of equations.

1 answer

Let's analyze the given system of equations to determine which statements are true. The equations are as follows:

  1. \( 2x - 7y = -13 \)
  2. \( -2x + 11y = 1 \)

To check the statements, we can display the system and perform the necessary calculations.

  1. The x-variable will be eliminated when adding the system of equations.
    If we add the two equations, the \( 2x \) from the first equation and the \( -2x \) from the second equation will cancel out: \[ (2x - 7y) + (-2x + 11y) = -13 + 1 \] This simplifies to: \[ 0 + 4y = -12, \] so this statement is true.

  2. The y-variable will be eliminated when adding the system of equations.
    No, the \( y \)-variable will not be eliminated; instead, we will be left with an expression for \( y \). This statement is false.

  3. The sum of the system of equations is \( 4y = -12 \).
    After adding the two equations, we got \( 4y = -12 \). This statement is true.

  4. x = 17
    We will find \( x \) and \( y \) by solving the system. Starting from \( 4y = -12 \): \[ y = -3. \] Substitute \( y = -3 \) back into one of the original equations to find \( x \): \[ 2x - 7(-3) = -13 \] \[ 2x + 21 = -13 \] \[ 2x = -34 \] \[ x = -17. \] Thus, \( x \) is not 17; this statement is false.

  5. y = -3
    From our previous calculations, we found that \( y = -3 \). This statement is true.

  6. There are infinitely many solutions to the system of equations.
    Since we obtained a unique solution \( (x, y) = (-17, -3) \), there are not infinitely many solutions. This statement is false.

Summary of True Statements:

  • The x-variable will be eliminated when adding the system of equations.
  • The sum of the system of equations is \( 4y = -12 \).
  • y = -3