Jawabanmu

2014-08-18T20:35:54+07:00
A. 2 (3- \sqrt{5} )+3(3 \sqrt{5)}
  = 6 - 2 \sqrt{5}+9 \sqrt{5}

b. 2(3- \sqrt{5}) - 3(3 \sqrt{5} )
  = 6-2 \sqrt{5}-9 \sqrt{5}

c.  (3- \sqrt{5}) ^{2} - (3 \sqrt{5} )^{2}
  = 9-6 \sqrt{5} +5-45
  = -41 - 6 \sqrt{5}

d. (3- \sqrt{5} -3 \sqrt{5} ) ^{2}
  = (3-4 \sqrt{5} ) ^{2}
  = 9 - 24 \sqrt{5} + 80
  = 89 - 24 \sqrt{5}

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