Question 953749
L=length; W=width=L-10m; A=area=L*W
{{{A=L*W}}}
{{{428m^2 =L*W}}} Substitute for W
{{{428m^2=L*(L-10m)}}}
{{{428m^2=L^2-10L}}} Subtract 428m^2 from each side
{{{0=L^2-10L-428m^2}}}*[invoke quadratic "L", 1, -10, -428 ]
{{{L=26.28}}} The length is 26.28 meters.
{{{W=L-10m=26.28m-10m=16.28m}}} ANSWER: The width is 16.28 meters.
CHECK:
{{{L*W=A}}}
{{{26.28m(16.28m)=428m^2}}}
{{{427.84m=428m}}} Discrepancy from rounding.