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Bài 4:
b: BC=5cm
Xét ΔABC có AD là phân giác
nên BD/AB=CD/AC
=>BD/3=CD/4
Áp dụng tính chất của dãy tỉ số bằng nhau, ta được:
\(\dfrac{BD}{3}=\dfrac{CD}{4}=\dfrac{BD+CD}{3+4}=\dfrac{5}{7}\)
Do đó; BD=15/7(cm); CD=20/7(cm)
1 I was told to be the best architect in this city
It was told that I was the best...city
2 The flowers were reported to have been killed by frost
It was reported that the flowers were killed...
3 The director is informed to be going to take..England
It is informed that the director is going....England
4 The meeting was announed to have been delayed until next week
It was announed that the meeting was..week
unpollute
deforestation
environmental
pollution
conservationists
prevention
extremely
environmentalist
protection
seriously
poisonous
Thay a = 2; b = -1 vào C, ta có:
\(C=\dfrac{\left(2+1\right)^2-1}{2^2-1}=\dfrac{3^2-1}{2^2-1}=\dfrac{8}{3}\)