Vẽ tia số hơi khó ta??

a) l---l---l---l---l---l---l---l---l---l---l---l---l--->

   0   1  2  3   4  5   6  7  8   9  10 11 12

b) 1a26 + 4b4 + 57c = 1000 + a.100 + 20 + 6 + 400 + b.10 + 4 + 500 + 70 + c

                                 = ( 1000 + 400 + 20 + 6 + 4 + 500 + 70 ) + ( a.100 + b.10 + c )

                                 = 2000 + abc

Vậy 1a26 + 4b4 + 57c = abc + 2000.

Tia số mình vẽ có thể bị lệch hoặc có lỗi gì đó, chỉ mong bạn thông cảm!

Học tốt nà~~

ỏ yêu qa :>

A. Choose the word whose underlined part is pronounced differently from that of the rest in each question.

1. A. monkey B. Monday C. change D. money

2. A. village B. gesture C. goal D. passenger

3. A. hour B. honest C. what D. who

4. A. children B. brochure C. French D. church

5. A wounded B. announce C. mountain D. louder

A. Choose the word whose underlined part is pronounced differently from that of the rest in each question.

1. A. monkey B. Monday (C. change) D. money

2. (A. village) B. gesture C. goal D. passenger

3. A. hour B. honest (C. what) D. who

4. A. children (B. brochure) C. French D. church

5. A wounded B. announce (C. mountain) D. louder

1.A. obey B. key C. grey D. survey

2.A ways B.days C. says D.stays

3.A. common B. happy C. complete D. joyful

4. dangerous B. expensive C. enormous D. convenient

1.A. obey B. key C. grey D. survey

2.A ways B.days C. says D.stays

3.A. common B. happy C. complete D. joyful

4. dangerous B. expensive C. enormous D. convenient

Giải:

Ta có: AB//CD \(\Rightarrow\widehat{AEE'}=\widehat{CE'N}\)

\(\Rightarrow\widehat{AEx}=\widehat{xEE'}=\widehat{CE'y}=\widehat{NE'y}=\dfrac{1}{2}\widehat{AEE'}=\dfrac{1}{2}\widehat{AE'E}\)

\(\Rightarrow\widehat{xEE'}=\widehat{yE'N}\) (2 góc đồng vị)

\(\Rightarrow\) Ex // E'y

1. Pick out the word whose primary stress mark is placed differently from that of others.

Ans: A . dangerous ( first syllable)

2. Choose the word whose underlined part is pronounced differently from that of others.

Ans : B . key

1-a

2-b

864 x 48 - 432 x 96 = 864 x 48 - 432 x 2 x 48 = 864 x 48 - 864 x 48 = 0

suy ra A < B

n_H2 = 0,4 mol

Đặt n_Al = x (mol); n_Fe = y (mol); ( x, y > 0 )

2Al + 6HCl \(\rightarrow\) 2AlCl₃ + 3H₂ (1)

x........3x...........................1,5x

Fe + 2HCl \(\rightarrow\) FeCl₂ + H₂ (2)

y........2y........................y

Từ (1)(2) ta có hệ pt

\(\left\{{}\begin{matrix}27x+56y=11\\1,5x+y=0,4\end{matrix}\right.\)

\(\Rightarrow\) \(\left\{{}\begin{matrix}x=0,2\\y=0,1\end{matrix}\right.\)

\(\Rightarrow\) %_Al = \(\dfrac{0,2.27.100}{11}\) \(\approx\) 49,1%

\(\Rightarrow\) %_Fe = \(\dfrac{0,1.56.100}{11}\) \(\approx\) 50,9%

\(\Rightarrow\) n_HCl = ( 3.0,2 ) + ( 0,1. 2 ) = 0,8 (mol)

\(\Rightarrow\) x = \(\dfrac{0,8}{0,5}\) = 1,6 (M)

Bài 1

1) Al + 4HNO₃ -> NO + 2H₂O +Al(NO₃)₃

2) Al + 4HNO₃ -> NO₂ + H₂O + Al(NO₃)₃

3) 8Al + 30HNO₃ -> 3N₂O + 15H₂O + 8Al(NO₃)₃

4) 8Al + 27HNO₃ -> 8NH₃ + 9H₂O + 8Al(NO₃)₃

 = 2/3 x 5/6 x ... x 779/780

= 4/6 x 10/12 x ... x 1558/1560

= 1 x 4 x 2 x 5 x ... x 38 x 41/ 2 x 3 x 3x 4 x ... x 39 x 40

= ( 1 x 2 x 3 x ... x 38) x ( 4 x 5 x ... x 41)/( 2 x 3 x 4 x .... x  39) x ( 3x 4 x ... x 40)

Triệt tiêu xong rồi đó bạn ơi! Chúng ta còn lại:41/39 x 3 = 41/117

good bye