Toán Lớp 9: thực hiện phép tính
1. √0,04.256
2. ( √8/3 – √24 + √50/3). √6
3.(7 √7-3 √28+ √63): √7
4.( √12+ √27- √3). √3
5. √160 ²-96 ²
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Toán Lớp 9: thực hiện phép tính
1. √0,04.256
2. ( √8/3 – √24 + √50/3). √6
3.(7 √7-3 √28+ √63): √7
4.( √12+ √27- √3). √3
5. √160 ²-96 ²
Comments ( 2 )
1, \sqrt{0,04}·256
=\sqrt{1/25}·256
=(\sqrt{1})/(\sqrt{25})·256
=1/5 · 256
=256/5
+ $\text{Nếu đề là:}$ \sqrt{0,04 ·256}
=\sqrt{1/25·256}
=(\sqrt{1})/(\sqrt{25})·\sqrt256
=1/5 · 16
=16/5
2, ( \sqrt8/3 – sqrt24 + \sqrt50/3) ·\sqrt6
=(-\sqrt24 + (\sqrt8+\sqrt50)/3)·6
=(-\sqrt24 + (2\sqrt2+5\sqrt2)/3)·6
=(-2\sqrt6 + (7\sqrt2)/3)·6
=((-6\sqrt6 +7\sqrt2)/3)·6
=-12\sqrt6 +14\sqrt2
3,(7 \sqrt7-3 \sqrt28+ \sqrt63): \sqrt7
=(7 \sqrt7-6 \sqrt7+ 3\sqrt7): \sqrt7
= 4\sqrt7: \sqrt7
=4
4,( \sqrt12+ \sqrt27- \sqrt3) ·\sqrt3
=( 2\sqrt3+ 3\sqrt3- \sqrt3) ·\sqrt3
=4\sqrt3 · \sqrt3
=12
5, \sqrt160 ^2-96 ^2
=160-9216
=-9056
=\sqrt{(160-96)(160+96)}
=\sqrt{64·256}
=\sqrt{64}·\sqrt{256}
=8·16
=128