Respuesta :
12 = a (-6 + 5) (-6 -6)
12 = a ( -1) (-12)
12 = a * 1 * 12
12 = 12a
divide 12a with 12
a = 1
12 = a ( -1) (-12)
12 = a * 1 * 12
12 = 12a
divide 12a with 12
a = 1