標題:
FORM 4 MATHS
發問:
1.John obtained 73,63 and 90 marks in 3 Mathematics tests and x marks in the final examination.If the weights given to the final examination.If the weights given to the final examination and to each test are in the ratio 4:1 and the weighted mean of John in Mathematics is 78.Find x.2.If the coefficient of x^1... 顯示更多 1.John obtained 73,63 and 90 marks in 3 Mathematics tests and x marks in the final examination.If the weights given to the final examination.If the weights given to the final examination and to each test are in the ratio 4:1 and the weighted mean of John in Mathematics is 78.Find x. 2.If the coefficient of x^1 in the expansion of (x-a)(x^2-3x) is -5, then a =?
Q1) Let x be the marks of the final exam (73 + 63 + 90 + 4x) / 7 = 78 226 + 4x = 546 4x = 320 x = 80 Q2) (x-a)(x^2-3x) = x^3 - 3x^2 - ax^2 + 3ax = x^3 - (3+a)x^2 + 3ax Given that coefficient of x = -5, then: 3a = -5 a = -5/3 ** little bit extra calculation.. ** If the coefficient of x^2 = -5, then: -(3+a) = -5 3+a = 5 a = 2
其他解答:
FORM 4 MATHS
發問:
1.John obtained 73,63 and 90 marks in 3 Mathematics tests and x marks in the final examination.If the weights given to the final examination.If the weights given to the final examination and to each test are in the ratio 4:1 and the weighted mean of John in Mathematics is 78.Find x.2.If the coefficient of x^1... 顯示更多 1.John obtained 73,63 and 90 marks in 3 Mathematics tests and x marks in the final examination.If the weights given to the final examination.If the weights given to the final examination and to each test are in the ratio 4:1 and the weighted mean of John in Mathematics is 78.Find x. 2.If the coefficient of x^1 in the expansion of (x-a)(x^2-3x) is -5, then a =?
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最佳解答:Q1) Let x be the marks of the final exam (73 + 63 + 90 + 4x) / 7 = 78 226 + 4x = 546 4x = 320 x = 80 Q2) (x-a)(x^2-3x) = x^3 - 3x^2 - ax^2 + 3ax = x^3 - (3+a)x^2 + 3ax Given that coefficient of x = -5, then: 3a = -5 a = -5/3 ** little bit extra calculation.. ** If the coefficient of x^2 = -5, then: -(3+a) = -5 3+a = 5 a = 2
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