經濟功課 急

As textbooks are made up of papers, hence, fall in papers' price will reduce the production cost of textbooks, the producers can increase the textbooks' supply, thus, shifting the supply curve to the right.
Number of students will increase the demand on textbooks as they will buy more textbooks, hence, the demand on textbooks would rise and demand curve will shift to the right.
The effect on equilibrium price would be uncertain, as it depends on the extents of both demand and supply curves movements. However, what we sure is that the equilibrium quantity must be increased.

假設紙張價格劇跌,而就學人數則上升
解釋為何上述轉變會影響教科書的供應和需求
紙張係教科書既生產因素
生產因素 -- >> 紙張價格 (P)劇跌
教科書的供應增加

就學人數上升 >>對教科書的需求增加

幅供需圖:
你畫到需求D 同埋供給線S 2條線都向右移
結果係P跌 Q跌