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If the Sum of three. numbers of an arithmetic sequence és 15 and the sum of their squares is then the numbers are 83, (a) 4,5,6 |
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Answer» Let a-d, a, a+d are the three numbers. Then sum = a-d+a+a+d = 15 3a = 15 a = 5 Sum of squares, (a-d)2+a2+(a+d)2 = 83 a2-2ad+d2+a2+a2+2ad+d2 = 83 3a2+2d2 = 83 Substitute a = 5 75+2d2 = 83 2d2 = 8 d2 = 4 So d = 2 Then the numbers are 3, 5, 7. |
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