Answer
$(-5,\infty)$
Work Step by Step
$-4x\lt20$
Solve for x by dividing each side of the equation by -4. Dividing by a negative requires you to reverse the inequality sign.
$-4x\div-4\gt20\div-4$
$x\gt-5$
This is written in interval notation as
$(-5,\infty)$
where the use of ( indicates that the solution set for x approaches but does not include -5.