Answer
$x\lt0$
Work Step by Step
Multiplying both sides by the $LCD=
28
$ and then using the properties of inequalities, the solution to the given inequality, $
\dfrac{x+3}{4}+\dfrac{x-5}{7}\lt\dfrac{1}{28}
,$ is
\begin{array}{l}\require{cancel}
7(x+3)+4(x-5)\lt1(1)
\\\\
7x+21+4x-20\lt1
\\\\
7x+4x\lt1-21+20
\\\\
11x\lt0
\\\\
x\lt\dfrac{0}{11}
\\\\
x\lt0
.\end{array}