1. -1<x<1 2. 0<x<2 3. 1<x<3
A. 1 only B. 2 only C. 3 only D. 1 and 2 only E. 2 and 3 only
(要步驟)
2.The difference of the roots of the equation 2x^2 -5x +k =0 is 7/2. Find k.
3. Suppose the graph of y =x^2 -2x -3 is given. In order to solve the quadratic equation 2x^2 -6x -3=0, Find the straight lines should be added to the given graph.
4. Let k be a constant. If X and B are the roots of the equation x^2 -3x +k = 0, then X^2 +3B =?
各位識既麻煩幫小弟解答一下><
最好詳細D,因為我怕睇唔明=3=THX
更新1:
第3題唔係好明x² - 2x - 3 = x + 3/2 點樣整出來=.= 同埋答案是 y=x- 3/2 應該唔知邊度正負號調轉左-.-
更新2:
同埋第1題點解2個答案乘埋細過0就係contain a root既=.=?
更新3:
其實唔係好明=.= 我照你講既求其整條式: y=x^2 -3x -18 個root既左邊定係右邊Y都係>0 既=.= 同埋如果1正1負乘埋<0 咁點解<0就姐係contain a root既=.= >0點解唔得既=0=?