KA YAN asked in 科學及數學數學 · 1 decade ago

數學好唔明!!!

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!

1 Answer

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  • 1 decade ago
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    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

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