Just switch the negative sign over to the answer. so if you had -x = 6, then just switch the sign over to the 6. You would have the answer of x=-6, which is the same thing as -x=6
Answer: This is the <u>Communitve Property</u> because the equation has the same thing on both sides, but the numbers "flip flopped" or switched around.
4 digit palindromes must be of form abba, so being required that you use both numbers, you only have two: 1221 and 2112
