Question

若不等式x+2/k>1+(x-3)/k^2的解是x>3,求k的值

Answer 1

x+2/k是指(x+2)/k吧

移项并通分【k(x+2)-k^2-(x-3)】/k^2>0

化简 (k-1)x-(k^2-2k-3)/k^2>0

即(k-1)x-(k^2-2k-3)>0 解得x>(k^2-2k-3)/(k-1)

其中k-1>0 因为除过来 >没变

(k^2-2k-3)/(k-1)=3 解得k=5舍k=0

答案是5