Respuesta :

use the substitution method
use the first equation, let y = k - x
plug y = k - x into the second equation
==> 2x + 3(k - x) = k + 1
==> 2x + 3k - 3x = k + 1
==> -x = k - 3k + 1
==> -x = -2k + 1
==> x = 2k - 1 is the answer
x = 2k - 1 is the answer