Question 71906
let's say the increase to each side is a meters
Then the expression for the area is
{{{(x+a)(x+a) = x^2 + 2ax + a^2}}}
{{{x^2 + 2ax + a^2 = x^2 + 18x + 81}}}
from this you can see that
{{{2a = 18}}} and
{{{a^2 = 81}}}
{{{a = 9}}} satisfies both of these, so
the length and width was increased by 9 meters