Please show all the steps
Thx a lot

唔講step,講啲key point自己領會吓先~(講咗答案係學唔到嘢,反而俾啲key point先有用)
(1)根=x位...將-4 同 -1/2 分別代入到條式(唔好同我玩同一條式個x都唔同),咁會出到一條聯立方程,再解
(2)用返ax^2+bx+c 之間abc的關係
(3)根和,又係有一條式(唔知F4教咗未>.< 因為我343學生就F.5 先教),之後又係會解到

再唔明就再問啦~
最後都講句,俾答案唔係萬能的,去到考試唔識做又係死>.<

(1)樓主亦可用sum of roots / product of roots的方法計, 個人覺得方便d
sum of roots = -9/m
-9/m = -4.5
m=2

product of roots = n/m
-4 x (-0.5) = n/2
n=4

(2)我會sub x=5 搵左k先,
25+5k-10=0
k=-3
-> 5x^2 - 3x -10 =0
x=5 or -2
The other root is -2.

(3) sum of root = -4(2-k)/(k-1)
-4(2-k)/(k-1) = 3
3k-3=-8+4k
k=5

4x^2 -12x+ 5 =0
x = 2.5 / 0.5

其實未知樓主有冇入program,
其實只要入左program, ed數其實好易,
加上基本上每1個topic都要用到