Answer
The positive values are $0\lt x \lt 21.6$.
Work Step by Step
Perimeter is
$=x+14.2+15.5$
The inequality is
Perimeter $<51.3$
$\Rightarrow x+14.2+15.5<51.3$
Add like terms.
$\Rightarrow x+29.7<51.3$
Subtract $29.7$ from each side.
$\Rightarrow x+29.7-29.7<51.3-29.7$
Simplify.
$\Rightarrow x<21.6$
Side must be greater than zero.
Hence, the positive values are $0\lt x \lt 21.6$.
