Question

Please help me with this!


show that {1,2} ⊆ x

Answer 1

The set
`\{x\mid x^4-x^3-x^2-6x+6=0\}` is the set of all values of
`x` that are solutions to the given equation. So all you need to do is check whether
`x=1` and
`x=2` satisfy the equation.

`x=1\implies 1^4-1^3-1^2-5+6=0`

`x=2\implies2^4-2^3-2^2-10+6=0`

The equation holds, so both 1 and 2 are solutions, and hence
`\{1,2\}` is a subset of the solutions.