Jawabanmu

2014-09-12T21:44:19+07:00
2. 6  \sqrt{4.2} -5  \sqrt{100.2} -12  \sqrt{2.4.9}
= 6.2 \sqrt{2} -5.10  \sqrt{2} -12.2.3 \sqrt{2}
=12 \sqrt{2} -50 \sqrt{2} -72 \sqrt{2}
= -110\sqrt{2}

3. 4(5- \sqrt{6} )(( \sqrt{3} + \sqrt{2} )
=4( 5 \sqrt{3} +5  \sqrt{2} - \sqrt{18} - \sqrt{12} )
=4( (5 \sqrt{3} +5  \sqrt{2} - 3 \sqrt{2} -2 \sqrt{3} ))
=4( 3 \sqrt{3} +2  \sqrt{2} )
=12  \sqrt{3} + 8 \sqrt{2}