數學好唔明!!! - Ans.fyi 參考答案

數學好唔明!!!

KA YAN

2007-12-22 1:06 am

1)solve the equation (開方11-3)x+6=0 and rationalize the result.
2)Mr.Ho walked 6km at an average speed of xkm/h. If he walks 1km/h slower on average,it takes him 12 minutes more to complete the same journey.Find his orginal average speed.
3)how many real solutions do the simultaneous equations{y=x^2+3x+3 have?
{2x-y+5=0
唔該教下我la!

回答 (1)

嘉裕

2007-12-22 2:17 am

✔ 最佳答案

詳細step唔寫,只講吓點計.

1)你當呢條係formula,將x變為subject咪得囉
Rationalization方面,分子分母乘(開方11+3)就得

2)先計如果Mr.Ho用x km/h嚟行所用嘅時間(in terms of x),再計如果Mr.Ho用(x-1) km/h(1km/h slower on average)嚟行所用嘅時間(in terms of x).最後根據12 minutes more 嚟solve equation
solve equation方面,左右都乘x(x-1)就可以

3)
y=x^2+3x+3----(1)
2x-y+5=0--------(2)
先用(2)Express y in terms of x,再將結果substitute入去(1)到,最後計discriminant

👍 0 👎 0