⑴设一次函数y=kx+b x=2.5,y=7.2 x=3,y=6带入得 2.5k+b=7.2 3k+b=6 解得k=-2.4,b=13.8 y=-2.4x+13.8 设二次函数y=ax^2+mx+n x=2.5,y=7.2 x=3,y=6 x=4,y=4.5带入求a=3/5,m=-5.7,n=17.7 y=0.6x^2-5.7x+17.7 设反比例函数y=t/x x=2.5,y=7.2代入得t=18 y=18/x x=4,x=4.5代入一次函数得y=4.2,y=3 x=4.5代入二次函数得y=4.2 x=3,x=4,x=4.5代入反比例函数得y=6,y=4.5,y=4 ...
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