296. Given the area and the difference of the sides of a rectangle, find its sides.
296. Paciolo's Solution: Let $a^{2}$ be the area of the rectangle and $d$ be the difference between the sides. The larger side is $x+\frac{d}{2}$, then the smaller side is $x-\frac{d}{2}$, hence $x^{2}-\frac{d^{2}}{4}=a^{2}, \quad$ from which $x=$ $=\sqrt{\frac{d^{2}}{4}+a^{2}}$; this is simpler than taking both sides as unknowns.