1. Long division:
3x^3+x^2 -2x -4 rem -14
3x-1 | 9x^4.........-7x^2-10x-10
..........9x^4-3x^3
...................3x^3-7x^2
...................3x^3- x^2
...........................-6x^2-10x
...........................-6x^2+ 2x
....................................-12x-10
....................................-12x+ 4
...........................................-14
2. Long division:
-4x^2 -6x -12 rem -19
x-2 | -4x^3+2x^2 + 5
........-4x^3+8x^2
..................-6x^2
..................-6x^2+12x
............................-12x+ 5
............................-12x+24
....................................-19
3. x^2+2x-15=(x+5)(x-3). So x+5 is a factor and the quotient is x-3 (no remainder).