Practice problem
Which of the following are irreducible by Eisenstein's criterion?
x3+3x2+6x+9x^3+3x^2+6x+9x3+3x2+6x+9
x3+4x2+4x+2x^3+4x^2+4x+2x3+4x2+4x+2
x5+3x4+6x2+12xx^5+3x^4+6x^2+12xx5+3x4+6x2+12x
x5−7x+49x^5-7x+49x5−7x+49
Type a concept, like “slope” or “photosynthesis”.