Answer
$[6, ∞)$
Work Step by Step
Plug the given conditions into an inequality. Put similar terms on either side. Then simplify by isolating $x$. The words "at least" or "at most" imply that a value is greater than or less than the other side.
$1-(x+3)+2x\geq4$
$-x-2+2x\geq4$
$x\geq6$
$[6, ∞)$