2 câu trả lời
$($$\sqrt{28}$$-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@
`#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`
Câu hỏi trong lớp
Xem thêm