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Mathematics
發問:
1. Which one of the numbers does not belong in the following series? 1-2-5-10-13-26-28-58 A.1 B.26 C.28 D.582.If the length of three sides of an isosceles triangles are (3x-8), (3x-6) and (5x-16), find the number of possible values for x?3. If a and b are real... 顯示更多 1. Which one of the numbers does not belong in the following series? 1-2-5-10-13-26-28-58 A.1 B.26 C.28 D.58 2.If the length of three sides of an isosceles triangles are (3x-8), (3x-6) and (5x-16), find the number of possible values for x? 3. If a and b are real numbers such that a+b
最佳解答:
1) 1-2-5-10-13-26-28-58 (1 , 2) (5 , 10) (13 , 26) ,...... (1 , 2) (2+3 , 10) (10+3 , 26) , the next term should be (26+3 , 58) i.e. (29 , 58) 28 does not belong in the following series , it should be 29 , ANSWER : (C) 2) 3 sides : (3x-8), (3x-6) and (5x-16), Case 1 : 3x-8 = 3x-6 , no solution. Case 2 : 3x-8 = 5x-16 x = 4 3 sides are 3*4-8 = 4 , 3*4-6 = 6 and 5*4-16 = 4 Case 3 : 3x-6 = 5x-16 x = 5 3 sides are 3*5-8 = 7 , 3*5-6 = 9 and 5*5-16 = 9 There are 2 possible values for x. 3)a+b 0 , a 0 , a b ......(2) or a 0 so - b
其他解答:
1.D 2.3x-8not equal to 3x-6 so it is not those isos. sides,because of this 3x-8=5x-16and 3x-6 also =5x-16 so x can be 4/5 3.D 2010-04-29 19:05:26 補充： a must be negative no. and if b is negative no. after a time b they will not be smaller than 0 so b must be positive number .at this moment the answer is very obvious ,
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