1. Solve the following system of equations using the method of GaussJordan elimination.(25%) ?1 + ?2 + 2?3 + 6?4 = 11 2?1 + 3?2 + 6?3 + 19?4 = 36 3?2 + 4?3 + 15?4 = 28 ?1 − ?2 − ?3 − 6?4 = −12