How does one prove that A intersecting B = A , iff A is a subset of B ?
How do I prove that -LSB- math -RSB- a ^ n + b ^ n -LSB- / math -RSB- is divisible by -LSB- math -RSB- a + b -LSB- / math -RSB- when -LSB- math -RSB- n -LSB- / math -RSB- is odd , and is never divisible by -LSB- math -RSB- a - b -LSB- / math -RSB- ?