Question 805529
Most of this is translating description into numeric symbols and relationships.


x = length
y = breadth
A = area using x and y
.
{{{x=y+3}}}, and {{{xy=A}}}, and conclude here that {{{(y+3)y=A}}}


Condition of {{{x+1}}} and {{{y+1}}}, the dimension size increase:
{{{(x+1)(y+1)=A+18}}}
Remember that we understood from given, {{{x=y+3}}}.
{{{(y+3+1)(y+1)=A+18}}}


This set of equations lets you solve for either A or y:
{{{y(y+3)=A}}} and {{{(y+4)(y+1)=A+18}}}


WHAT NOW TO DO:
Solve each of those for A, and then equate the formulas.  Solve for y.  Use the value to solve for x.