A point charge of $4\mathrm{.}9$ uc is placed at the origin $($x$1=0)$ of a coordinate system, and another charge of $1\mathrm{.}5$ uc is placed placed on the x$-$axis at x$2=0\mathrm{.}29$m $$

Part $($a$)$Where on the x$-$axis can a third charge be placed in meters so that the net force on it is zero?

$50\%$Part $($b$)$What if both charges are positive; that is$,$ what if the second charge is $1\mathrm{.}5$ uc$?$