Jawabanmu

2014-08-08T14:56:41+07:00
A. 4a-6b+5a+3b-2
  = 4a+5a-6b+3b-2
  = 9a-3b-2
b. 40xy-45xz-40xy-72yz
  = 40xy-40xy-45xz-72yz
  =-45xz-72yz
2014-08-08T15:14:53+07:00
A. 4-2(a+3b)+5a+3b-2
   =2(a+3b)+5a+3b-2
   =2a+6b+5a+3b-2
   =2a+5a+6b+3b-2
   =7a+9b-2
b. 8y(5x-9z)-5x(8y)-9z
   =40xy-72yz-40xy+40xz
   =40xy-40xy-72+40xz
   = -72+40xz
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