đề bài

21/4 bằng bn lần 1/8

bài giải

ta có:21/4:1/8=ko có 

suy ra ko có số nào thỏa mãn đề bài đã cho.

mk ko hiểu rõ đề cho lắm bn có thể viết dấu ko

viết lại bài đi,sai chính tả nhiều quá!!

Bài 1

1/ D

2/ A

3/ D

4/ A

5/ A

1 plays

2 are reading

3 sing

4 do - do, help

5 is teaching

7 visited

8 doesn't like

9 watch

10 gets - has - brushes - goes - has

11 played - was

12 met

13 are going to have

14 did - do , planted

15 didn't come

16 paint

17 taught

18 have never been

19 takes

20 have - had 

21 received

22 is going to invite

23 is waiting

24 talked

25 is going to travel

26 went - didn't buy

27 doesn't learn - will fail

28 washes

29 will be - watches

30 will phone

2 are reading

3 sings

4 do - do - help

5 is teaching

7 visited 

8 doesn't like

9 watch

10 gets - has

6. 10 brushes - goes

6. 30 has

11 played - was

12 met

13 will have

14 did - do - planted

15 didn't come

16 paint

17 taught

1 plays

2 are reading

3 sing

4 do - do, help

5 is teaching

7 visited

8 doesn't like

9 watch

10 gets - has - brushes - goes - has

11 played - was

12 met

13 are going to have

14 did - do , planted

15 didn't come

16 paint

17 taught

18 have never been

19 takes

20 have - had 

21 received

22 is going to invite

23 is waiting

24 talked

25 is going to travel

26 went - didn't buy

27 doesn't learn - will fail

28 washes

29 will be - watches

30 will phone

giai thi de nhung cac bạn k h nen k muon giai ,noi that long chu k dụ h

bạn o LA hả mk giai cho bạn nhe;

bạn thay p(x) =0 va x=5 la tim dc a thoi ( vi chu so tan cung .....=5)

2.5⁴ +a.5³ + 2a.5 -980 = 0

a = 71/27

1.How does your dad go to work ?

2. Where does she rode her bike ?

3. What should I do when I hava toothache ?

4. Is there any butter in the fridge ?

5. When are they going to BaNa Hill ?

1 How does your dad go to work?

2. Where does she rode her bike ?

3. what shoild I do when I hava toothache?

4 Is there any butter in the fridge?

5 When are they going to BaNa Hill ?

1. How does your dad go to work?

2. Where did she rode her bike?

3. What should I do when I have tootache?

4. Is there any butter in the fridge?

5. When are they going to BaNa Hill?

2:

1: =7x(x-y)-5(x-y)

=(x-y)(7x-5)

2: =(x^2-y^2)-(4x-4y)

=(x-y)(x+y)-4(x-y)

=(x-y)(x+y-4)

3: =(x^2+2xy+y^2)-(2x+2y)+1

=(x+y)^2-2(x+y)+1

=(x+y-1)^2

\(\frac{3}{x+5}=15\%\)

\(\frac{3}{x+5}=\frac{15}{100}\)

\(\frac{3}{x+5}=\frac{3}{20}\)

\(\Rightarrow x+5=20\)

\(\Rightarrow x=20-5\)

\(\Rightarrow x=15\)

~ Thiên mã ~

\(\frac{3}{x}+5=15\%\)

\(\frac{3}{x}+5=\frac{3}{20}\)

\(\frac{3}{x}=\frac{3}{20}-5\)

\(\frac{3}{x}=\frac{-97}{20}\)

\(\Rightarrow\left(-97\right)x=3.20\)

\(\Rightarrow\left(-97\right)x=60\)

\(\Rightarrow x=60:\left(-97\right)\)

\(\Rightarrow x=\frac{-60}{97}\)

~ Hok tốt ~

\(\frac{3}{X}\)+5=\(\frac{15}{100}\)

\(\frac{3}{X}\)+5=\(\frac{3}{20}\)

\(\frac{3}{X}\)=\(\frac{3}{20}\)-5

\(\frac{3}{X}\)=\(-\frac{97}{20}\)

X=\(-\frac{97}{20}\)\(:\)3

X=\(-\frac{97}{60}\)

x-3=0/8

x-3=0

   x=0+3

   x=3

\(8\left(x-3\right)=0\)

\(x-3=0\)

\(x=3\)

vay \(x=3\)