a) 4^10.8^15
b) 8^2.25^3
minh can gap lam
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có tất cả số số là:
(678-2):2+1=339(số)
tổng trên là:
(2+678)x339:2=115260
chúc bạn học giỏi
\(B=...\)
\(=\left(4+12+20+...+92\right)+\left(8+16+24+...+96\right)-\left(8+16+...+96\right)\)
\(=4+12+20+...+92\)
\(=\left(4+92\right)\times\left[\frac{\left(92-4\right)}{8}+1\right]=96\times12=1152\)
\(a,x-7\frac{5}{8}=1\frac{1}{4}\)
=> \(x-\frac{61}{8}=\frac{5}{4}\)
=> \(x=\frac{5}{4}+\frac{61}{8}\)
=> \(x=\frac{10}{8}+\frac{61}{8}=\frac{71}{8}=8\frac{7}{8}\)
\(b,x+7\frac{5}{8}=9\frac{1}{4}\)
=> \(x+\frac{43}{5}=\frac{37}{4}\)
=> \(x=\frac{37}{4}-\frac{43}{5}=\frac{13}{20}\)
\(c,\left[x-7\frac{5}{8}\right]:\frac{1}{2}=3\)
=> \(\left[x-\frac{61}{8}\right]=3\cdot\frac{1}{2}\)
=> \(\left[x-\frac{61}{8}\right]=\frac{3}{2}\)
=> \(x-\frac{61}{8}=\frac{3}{2}\)
=> \(x=\frac{3}{2}+\frac{61}{8}=\frac{12}{8}+\frac{61}{8}=\frac{73}{8}=9\frac{1}{8}\)
d, \(\frac{x}{1\cdot3}+\frac{x}{3\cdot5}+\frac{x}{5\cdot7}+...+\frac{x}{97\cdot99}=99\)
=> \(\frac{x}{2}\left[\frac{2}{1\cdot3}+\frac{2}{3\cdot5}+\frac{2}{5\cdot7}+...+\frac{2}{97\cdot99}\right]=99\)
=> \(\frac{x}{2}\left[1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+...+\frac{1}{97}-\frac{1}{99}\right]=99\)
=> \(\frac{x}{2}\left[1-\frac{1}{99}\right]=99\)
=> \(\frac{x}{2}\cdot\frac{98}{99}=99\)
=> \(\frac{98x}{198}=99\)
=> 98x = 99 . 198
=> 98x = 19602
=> x = 19602 : 98 = 9801/49
a) \(x-7\frac{5}{8}=1\frac{1}{4}\)
=> \(x=\frac{5}{4}+\frac{61}{8}\)
=> \(x=\frac{71}{8}\)
b) \(x+7\frac{5}{8}=9\frac{1}{4}\)
=> \(x=\frac{37}{4}-\frac{61}{8}\)
=> \(x=\frac{13}{8}\)
c) \(\left(x-7\frac{5}{8}\right):\frac{1}{2}=3\)
=> \(x-\frac{61}{8}=3.\frac{1}{2}\)
=> \(x-\frac{61}{8}=\frac{3}{2}\)
=> \(x=\frac{3}{2}+\frac{61}{8}\)
=> \(x=\frac{73}{8}\)
d) \(\frac{x}{1.3}+\frac{x}{3.5}+...+\frac{x}{97.99}=99\)
=> \(x.\frac{1}{2}.\left(\frac{2}{1.3}+\frac{2}{3.5}+...+\frac{2}{97.99}\right)=99\)
=> \(\frac{1}{2}x\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+....+\frac{1}{97}-\frac{1}{99}\right)=99\)
=> \(x\left(1-\frac{1}{99}\right)=99:\frac{1}{2}\)
=> \(x.\frac{98}{99}=198\)
=> \(x=198:\frac{98}{99}=\frac{9801}{49}\)
4 has not been - broke
5 did you - was
6 have youy ever been
II
1 go
2 were
3 eats
7 does - won't worry
8 had played - would have won
9 will - do
10 were - would go
14 would have written
15 won't go
16 tries
17 spoke
19 finish - will go
20 see - ask
Rewrite
1 The man who doesn't work hard can't earn more money
3 If my friend and I had enough money, we would buy a house of our town
4 If the weather were better now, we could go for a walk
5 If I knew his addres, I would give it to you
6 If he worked slowly enough, he wouldn't make
7 If I were sent to proson, she would visit me
8 If I won a big prize in a lottery, I would give up my job
9 If the doctor weren't so late, he could see many patients
10 If tickets weren't expensive, we would visit them in Ha Noi
III
1 were
2 would visit
3 would give
Cố tình trồng cây
Cây hoa ko lên
Vô tình hít thở
Vậy mak tăng cân ....
hết ak
Bạn!
Đi qua cánh cửa
Từ từ bước tới
Băn khoăn suy nghĩ
Bạn bè là gì
Người bạn cơ tri
Tình bạn chúng ta
Như một bản nhạc
Chưa từng khắc ghi
~ Hok tốt ~
a)\(4^{10}.8^{15}.\left(2^{10}\right)^2.\left(2^{15}\right)^3=2^{20}.2^{30}=2^{50}\)
b)\(8^2.25^3=\left(2^2\right)^3.\left(5^3\right)^2=2^6.5^6=\left(2.5\right)^6=10^6\)
de mh giai thik : cau a ) vi chung chua cung co so nen ta doi ra thanh co so giong . nhau ta chi viec lay so mu cong voi nhau
cau b ) ta không thể đổi ra cùng cơ số được nên ta đổi ra cung so mu. thi ta chi viec nhan hai co so voi nhau giu nguyen mu
sai chỗ nào thì mấy bạn sữa giùm mình nha mình mới học lớp 5 ak
nhanh len may ban oi\