Help me with finding lengths of both questions please​

(01.02 lc) angle abc has point e on ray ba and point d on ray bc. points e and d are equidistant from point b. to bisect angle abc, which of the following needs to be identified for the construction? the distance between points e and d the point in the angle that is equidistant from points e and d the endpoint of rays ba and bc the point outside of the angle that is equidistant from points e and d

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Suppose the equation ||x-a|-b|=2008 has 3 distinct real roots and a not =0. find the value of b.