Question 977695
A lesson dedicated to this exact type of exercise is here:


<a href="http://www.algebra.com/my/FIND-RECTANGLE-DIMENSIONS-USING-GIVEN-PERIMETER-AND-AREA.lesson?content_action=show_dev">FIND RECTANGLE DIMENSIONS USING GIVEN PERIMETER AND AREA</a>
http://www.algebra.com/my/FIND-RECTANGLE-DIMENSIONS-USING-GIVEN-PERIMETER-AND-AREA.lesson?content_action=show_dev