x-y-3≦0
若(x,y)為聯立不等式 { 2x+y-9≧0 所表示圖形上的任一點,
3x+2y-44≦0
2x-y+1≧0
且 P = x+ky 在 (10,7)有最大值產生,則實數k的範圍為 ?
ans: -1 < k < 2/3
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x-y-3 = 0
{ ====>(x,y) = (4,1)
2x+y-9 = 0
3x+2y-44=0
{ ===> (x,y) = (6,13)
2x-y+1=0
x-y-3 = 0
{ ===> (x,y) = (10,7)
3x+2y-44=0
2x+y-9 = 0
{ ===> (x,y) = (2,5)
2x-y+1=0
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