Jawapan

  • Pengguna Brainly
2016-01-10T21:51:38+08:00
T1 = 11 - x
T2 = 2x + 1
T3 = 3x + 1
T1 = ?
S9 = ?

T3 - T2 = T2 - T1
3x + 1 - ( 2x + 1 ) = 2x + 1 - ( 11 - x )
3x + 1 - 2x - 1 = 2x + 1 - 11 + x
3x - 2x - 2x - x = 1 - 11 - 1 + 1
- 2x = - 10
x = 5

T1 = 11 - ( 5 )
     = 6

d = T2 - T1
   = 2 ( 5 ) + 1 - 6
   = 11 - 6
   = 5

S9 = 9 / 2 ( 2 ( 6 ) + 8 ( 5 ) )
      = 9 / 2 ( 12 + 40 )
      = 54 + 180
      = 234


      
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