Đáp án:
Giải thích các bước giải:
a) Xét VP = (a+b)³ - 3ab(a+b) = a³ + 3a²b + 3ab² +b³ - 3a²b - 3ab² = a³ + b³ = VT
⇒ ĐPCM
b) Xét VP = (a-b)³ + 3ab(a+b) = a³ - 3a²b + 3ab² - b³ + 3a²b - 3ab² = a³ - b³ = VT
`a³ + b³ = (a + b)³ - 3ab(a + b)`
`=a³+ 3a²b +3ab²+b³ -3a²b -3ab²`
`=a³+b³`
`a³ - b³ = (a - b)³ + 3ab(a - b)`
`=a³ -3a²b -3ab^2-b^3+3a²b +3ab²`
`=a^3-b^3`
A. suppy the correct form of the verbs in paentheses: 1. they (introduce) a new video game next month. 2. I often (listen) to music before (go) to bed. 3.Lan is very hungry now because she (not eat) enough this morning. 4. Why don't we (go) to the canteen ? 5. At present, we (rehearse) a play. Nam (play) the flute. 6. We (see) a movie tomorrow. You (join) us ? 7. The River Nile (rise) in Central Afical. 8. John often (stay) in a hotel when he (come) to town, but tonight he (stay) with us. 9.It takes us about two hours (clim) to the top of the mountain. 10. Architects (make) the plans of buildings. 11.Listen ! Someone (knock) at the door. 12. The children must (be) back by six o'clock. 13. Wood (float) on water, but iron (not float). 14.Columbus (discover) America more than 400 years ago. 15.My father (play) roller-skating when he (be) a child. 16.We prefer (gather) around TV after dinner. 17.I (be) twenty-five next August. 18. Thanks for (bring) it for me.
chứng tỏ rằng b.25^25-25^24 chia hết cho 24 c.(7^6+7^5-7^4) chia hết cho 11
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Trong các hàm số sau hàm số nào là hàm số lũy thừa
Chuyển câu bị động giúp e vs akkk
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