Question 175049
"If the length is decreased by 10 in." is the same as saying 4x-10, and "if the width is increased by 2 in." is the same as saying x+2.  So the perimeter being 80 is equivalent to
{{{2(4x-10)+2(x+2)=80}}}
{{{8x-20+2x+4=80}}}
{{{10x-16=80}}}
{{{10x=96}}}
{{{x=9.6}}}
So the original field was 9.6 in by 38.4 in.