AD為商品市場(IS)及貨幣市場(LM)之均衡,故聯立將利率r消除即可:
IS: Y=2(6,400+250r)=12,800+2500r ...(1)LM: Y=4(Ms/P)+500r=4×2,400÷P+500r=9,600÷P+500r ...(2)
(1)+(2)=> 2Y=12,800+9,600÷P=> Y=6,400+4,800÷P