Question

用一般解方程,最好二元一次方程甲物品30件,乙物品28件,共花290.4元.每件甲物品比乙物品贵0.4元.甲乙两物品价格

Answer 1

解 设：甲物品X元,乙物品有y元

{ X-Y=0.4 (1)

{ 30X+27Y=290.4 (2)

由题意得X=0.4+Y

带入（2）30(0.4+Y)+27y=290.4

12+30y+27y =290.4

12+57y =290.4

57y =290.4-12

57y =278.4

y =278.4/57

y =