The correct answer for the given sentence is - "The teacher is new and good".
"The new teacher is good" would be "المعلمة الجديدة جيدة".
If "new" is defining the "teacher" as in "new teacher", then both words have to have the same gender, number and definiteness. Since "the teacher" is definite (has an ال prefix), the adjective will also need to be definite. So المعلمة الجديدة means "the new teacher"; and جيدة means "is good".
Hope this helps.