Solve the equation `x^(2)-5|x|+6=0`

Explanation

The given equation is equivalent to the collection of systems
`{(x^(2)-5x+6=0, "if"xge0),(x^(2)+5x+6=0, "if"xlt0):}implies{((x-2)(x-3)=0,"if"xge0),((x+2)(x+3)=0, "if"xlt0):}`
Hence the solutions of the given equation are
`x_(1)=2,x_(2)=3,x_(3)=-2,x_(4)=-3`