saat harga barang Rp 5,00 per unit,jumlah permintaan 10unit .adapun saat harga barang naik mnjd Rp7,00 per unit,jmlh prmintaan mjd 6 unit.fungsi permintaan brg

(P-P1) / (P2-P1) = (Q-Q1) / (Q2-Q1)
(P-5) / (7-5) = (Q-10) / (6-10)
(P-5) / (2) = (Q-10) / (-4)
-4(P-5) = 2(Q-10)
-4P+20 = 2Q-20
2Q = -20-20+4P
2Q = -40+4P
Q = -20+2P

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