Let x--------> <span>the rectangle's length y-------> </span><span>the rectangle's width
we now that Area of rectangle=x*y Area=256 cm</span>² <span>256=x*y-------> equation 1
y=4x-48------> y=4x-48------> equation 2
substitute equation 2 in equation 1
256=x*[4x-48]-----> 256=4x</span>²-48x 4x²-48x-256=0 <span> using a graph tool----> to resolve the second order equation see the attached figure the solution is x=16 cm y=4x-48----> y=4*16-48-----> y=16 cm
is a square
the answer is </span>the rectangle's length is 16 cm