Which two equations form a system with infinite solutions (same y intercepts) ?

1. y=5x-4
2. y=-2x+3
3. y=3x+1
4. 2y=6x+2
5. y-5x=2
6. y-4x+1=0
*

1 answer

To form a system with infinite solutions, two equations must represent the same line, which means they must be equivalent in form. This occurs when they have the same slope and y-intercept.

Let's analyze the equations you've provided to determine which two are equivalent:

  1. y = 5x - 4
    This has a slope of 5 and a y-intercept of -4.

  2. y = -2x + 3
    This has a slope of -2 and a y-intercept of 3.

  3. y = 3x + 1
    This has a slope of 3 and a y-intercept of 1.

  4. 2y = 6x + 2
    Dividing through by 2 gives: \[ y = 3x + 1 \]
    This has a slope of 3 and a y-intercept of 1 (same as equation 3).

  5. y - 5x = 2
    Rearranging gives: \[ y = 5x + 2 \]
    This has a slope of 5 and a y-intercept of 2.

  6. y - 4x + 1 = 0
    Rearranging gives: \[ y = 4x - 1 \]
    This has a slope of 4 and a y-intercept of -1.

After analyzing each equation, we can see:

  • Equations 3 and 4 are equivalent because they simplify to \(y = 3x + 1\).
  • All other pairs of equations have different slopes or y-intercepts.

Therefore, the two equations that form a system with infinite solutions are 3 and 4.