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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 9: (√28 -2 √14 + √7) √7 +7 √ 8 Giúp e zới ạ

Toán Lớp 9: (√28 -2 √14 + √7) √7 +7 √ 8
Giúp e zới ạ

Comments ( 2 )

  1. $($$\sqrt{28}$$-2$$\sqrt{14}$$+$$\sqrt{7}$$)$$\sqrt{7}$$+7$$\sqrt{8}$
    $=$$\sqrt{7}$$.$$(3$$\sqrt{7}$$-2$$\sqrt{14}$$)+14$$\sqrt{2}$
    $=21-14$$\sqrt{2}$$+14$$\sqrt{2}$
    $=21$
    @Nobitao@

  2. #huy
    (\sqrt{28} -2 \sqrt{14} + \sqrt{7}) \sqrt{7} +7 \sqrt{8}
    =(2\sqrt{7}-2\sqrt{14}+\sqrt{7})\sqrt{7}+7\sqrt{8}
    =3\sqrt{7}.\sqrt{7}-2\sqrt{14}.\sqrt{7}+7\sqrt{8}
    =21-14\sqrt{2}+14\sqrt{2}
    =21
     

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222-9+11+12:2*14+14 = ? ( )