(1)y=210-10x (0<x≤15且x为正整数)
变式一:
y=(50+x-40)(210-10x)
化简得
y=-10x²+110x+2100 (0<x≤15且x为正整数)
变式二:
40<x≤50且x为正整数时:
y=210(x-40)
50<x≤65且x为正整数时:
y=(x-40)[210-10(x-50)]
变式三:
0<x≤10且x为正整数时:
y=210x
10<x≤15且x为正整数时:
y=x[210-10(x-50)]
(1)y=210-10x (0<x≤15且x为正整数)
变式一:
y=(50+x-40)(210-10x)
化简得
y=-10x²+110x+2100 (0<x≤15且x为正整数)
变式二:
40<x≤50且x为正整数时:
y=210(x-40)
50<x≤65且x为正整数时:
y=(x-40)[210-10(x-50)]
变式三:
0<x≤10且x为正整数时:
y=210x
10<x≤15且x为正整数时:
y=x[210-10(x-50)]