Question 899345
Length L, width w.
{{{L-w>30}}} and {{{2w+2L=480}}}.


w+L=240
w=240-L
-
substitute into the inequality.
{{{L-(240-L)>30}}}
{{{L-240+L>30}}}
{{{2L>30+240}}}
{{{2L>270}}}
{{{highlight(L>135)}}}
-
Reuse w+L=240.
{{{L=240-w}}}.
Substitute again, into inequality:
{{{240-w-w>30}}}
{{{240-2w>30}}}
{{{-2w>30-240}}}
{{{2w<240-30}}}
{{{2w<210}}}
{{{highlight(w<105)}}}


*--------------------------------------------------------------*
The acceptable interval on L is {{{L>135}}};
and acceptable interval on w is {{{0<w<105}}}.
An equation to relate w and L may be {{{highlight(w+L=240)}}}, along with the stated restrictions on L and w.
-