✔ 最佳答案
首先解方程 2x²- 7x + 4 = 0
x = {-(-7) ± √[(-7)² - 4*(2)*(4)]} / [2*(2)]
x = (7 + √17)/4 或 x= (7 - √17)/4
解不等式:
2x² - 7x + 4 < 0
[x - (7 - √17)/4] [x - (7 + √17/4)] < 0
當 x < (7 - √17)/4: [x - (7 -√17)/4] [x - (7 + √17/4)] > 0
當 (7 - √17)/4< x < (7 + √17)/4: [x - (7 -√17)/4] [x - (7 + √17/4)] < 0
當 x > (7 + √17)/4: [x - (7 - √17)/4] [x - (7 + √17/4)] >0
答案: (7 - √17)/4 < x < (7 + √17)/4