let's subtract then: 3x2 - 2x + 3 - (6x2 - 4x + 3)
taking out of the bracket with a changed sign: (there is a minus in front of the bracket)
3x2 - 2x + 3 - 6x2 + 4x - 3
let's reshuffle them so that similar terms are together:
3x2 - 6x2 - 2x + 4x + 3 - 3
Adding up similar terms:
-3x2 + 2x - that's our option 2!
