bạn vào link này để tham khảo nha: Danh sách động từ bất quy tắc (tiếng Anh) – Wikipedia tiếng Việt

#maymay#

91 có đc ko bạn

nFe2O3=24/160=0,15(mol)

Fe2O3+3H2--t*->2Fe+3H2O(1)

0,15____0,45____0,3

Fe2O3+2Al--->Al2O3+Fe(2)

0,15___0,3___________0,15

Fe2O3+3CO--->2Fe+3CO2(3)

0,15____0,45___0,3

(1)VH2=0,45.22,4=10,08(l)

mFe=0,3.56=16,8(g)

(2)mAl=0,3.27=8,1(g)

mFe=0,15.56=8,4(g)

(3)VCO=0,45.22,4=10,08(l)

mFe=0,3.56=16,8(g)

\(1,x:\left(-\dfrac{1}{3}\right)^3=\left(-\dfrac{1}{3}\right)\\ \Leftrightarrow x=\left(-\dfrac{1}{3}\right)\times\left(-\dfrac{1}{3}\right)^3\\ \Leftrightarrow x=\left(-\dfrac{1}{3}\right)^4=\dfrac{1}{81}\\ 2,\left(\dfrac{4}{5}\right)^5.x=\left(\dfrac{4}{5}\right)^7\\ \Leftrightarrow x=\left(\dfrac{4}{5}\right)^7:\left(\dfrac{4}{5}\right)^5=\left(\dfrac{4}{5}\right)^{7-5}=\left(\dfrac{4}{5}\right)^2=\dfrac{16}{25}\)

\(3,\left(x+\dfrac{1}{2}\right)^2=\dfrac{1}{16}\\ \Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=\dfrac{1}{4}\\x+\dfrac{1}{2}=-\dfrac{1}{4}\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{4}\\x=-\dfrac{3}{4}\end{matrix}\right.\)

\(4,\left(3x+1\right)^3=-27\\ \Leftrightarrow\left(3x+1\right)^3=\left(-3\right)^3\\ \Leftrightarrow3x+1=-3\\ \Leftrightarrow3x=-4\\ \Leftrightarrow x=-\dfrac{4}{3}\)

\(5,\left(\dfrac{1}{2}\right)^2.x=\left(\dfrac{1}{2}\right)^5\\ \Leftrightarrow x=\left(\dfrac{1}{2}\right)^5:\left(\dfrac{1}{2}\right)^2\\ \Leftrightarrow x=\left(\dfrac{1}{2}\right)^{5-2}=\left(\dfrac{1}{2}\right)^3=\dfrac{1}{8}\)

\(6,\left(-\dfrac{1}{3}\right)^3.x=\dfrac{1}{81}\\ \Leftrightarrow\left(-\dfrac{1}{3}\right)^3.x=\left(-\dfrac{1}{3}\right)^4\\ \Leftrightarrow x=\left(-\dfrac{1}{3}\right)^4:\left(-\dfrac{1}{3}\right)^3=-\dfrac{1}{3}\)

\(7,\left(2x-3\right)^2=16\\ \Leftrightarrow\left[{}\begin{matrix}2x-3=4\\2x-3=-4\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{7}{2}\\x=-\dfrac{1}{2}\end{matrix}\right.\)

\(8,\left(x-\dfrac{2}{3}\right)^3=\dfrac{1}{27}\\ \Leftrightarrow\left(x-\dfrac{2}{3}\right)^3=\left(\dfrac{1}{3}\right)^3\\ \Leftrightarrow x-\dfrac{2}{3}=\dfrac{1}{3}\\ \Leftrightarrow x=\dfrac{1}{3}+\dfrac{2}{3}=\dfrac{3}{3}=1\)

`@` `\text {Ans}`

`\downarrow`

(Vế 1)

`1.`

`x \div(-1/3)^3 =-1/3`

`=> x= (-1/3) \times (-1/3)^3`

`=> x= (-1/3)^4`

`2.`

`(4/5)^5 *x = (4/5)^7`

`=> x = (4/5)^7 \div (4/5)^5`

`=> x=(4/5)^2`

`3.`

`(x+1/2)^2 =1/16`

`=> (x+1/2)^2 = (+-1/4)^2`

`=>`\(\left[{}\begin{matrix}x+\dfrac{1}{2}=\dfrac{1}{4}\\x+\dfrac{1}{2}=-\dfrac{1}{4}\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}x=\dfrac{1}{4}-\dfrac{1}{2}\\x=-\dfrac{1}{4}-\dfrac{1}{2}\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}x=-\dfrac{1}{4}\\x=-\dfrac{3}{4}\end{matrix}\right.\)

`4.`

`(3x+1)^3 = -27`

`=> (3x+1)^3 = (-3)^3`

`=> 3x+1=-3`

`=> 3x=-3-1`

`=> 3x =-4`

`=> x=-4/3`

`5.`

`(1/2)^2*x=(1/2)^5`

`=> x=(1/2)^5 \div (1/2)^2`

`=> x=(1/2)^3`

`6.`

`(-1/3)^3*x=1/81`

`=> (-1/3)^3*x = (1/3)^4`

`=> x= (1/3)^4 \div (-1/3)^3`

`=> x=(-1/3)`

`7.`

`(2x-3)^2 = 16`

`=> (2x-3)^2 = (+-4)^2`

`=>`\(\left[{}\begin{matrix}2x-3=4\\2x-3=-4\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}2x=7\\2x=-1\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}x=\dfrac{7}{2}\\x=-\dfrac{1}{2}\end{matrix}\right.\)

`8.`

`(x-2/3)^3 = 1/27`

`=> (x-2/3)^3 = (1/3)^3`

`=> x-2/3=1/3`

`=> x=1/3 + 2/3`

`=> x=1`

\(2,\left(\dfrac{2}{3}x-\dfrac{1}{3}\right)^5=\dfrac{1}{243}\\ \Leftrightarrow\left(\dfrac{2}{3}x-\dfrac{1}{3}\right)^5=\left(\dfrac{1}{3}\right)^5\\ \Leftrightarrow\dfrac{2}{3}x-\dfrac{1}{3}=\dfrac{1}{3}\\ \Leftrightarrow\dfrac{2}{3}x=\dfrac{1}{3}+\dfrac{1}{3}=\dfrac{2}{3}\\ \Leftrightarrow x=\dfrac{2}{3}:\dfrac{2}{3}=1\)

\(4,\left(2x-1\right)^{10}=49^5\\ \Leftrightarrow\left(2x-1\right)^{10}=\left(7^2\right)^5\\ \Leftrightarrow\left(2x-1\right)^{10}=7^{10}\\ \Leftrightarrow2x-1=7\\ \Leftrightarrow2x=8\\ \Leftrightarrow x=4\)

\(5,x:5^2=\left(\dfrac{3}{5}\right)^2:3^2\\ \Leftrightarrow x:5^2=\dfrac{9}{25}:9\\ \Leftrightarrow x:25-\dfrac{1}{25}\\ \Leftrightarrow x=\dfrac{1}{25}\times25=1\)

\(8,\left(2x-5\right)^4=-81\)

Xem lại đề nhé số mũ chẵn thì phải ra chẵn chứ

Sửa đề \(\left(2x-5\right)^4=81\\ \Leftrightarrow\left(2x-5\right)^4=3^4\\ \Leftrightarrow2x-5=3\\ \Leftrightarrow2x=8\\ \Leftrightarrow x=4\)

Phần bên này mình chỉ làm những câu khác và khó hơn 1 tý thôi còn các câu còn lại bạn có thể tự làm được nhé 

n_Zn = 0,25 mol

n_HCl = 0,2 mol

Zn + 2HCl → ZnCl₂ + H₂

Đặt tỉ lệ ta có

0,25 > \(\dfrac{0,2}{2}\)

⇒ Zn dư

⇒ V_H2 = 0,1.22,4 = 2,24 (l)

n_Zn = \(\dfrac{16,25}{65}=0,25\) mol

n_HCl = \(\dfrac{7,3}{36,5}=0,2\) mol

Pt: Zn + 2HCl --> ZnCl₂ + H₂

..............0,2 mol---------> 0,2 mol

Xét tỉ lệ mol giữa Zn và HCl:

\(\dfrac{0,25}{1}>\dfrac{0,2}{2}\)

Vậy Zn dư

V_H2 thu được = 0,2 . 22,4 = 4,48 (lít)

CMR: 3^2n+3^n+1

=> 3^2n+3^n+1

= 3^(2n+n)+1

= 3^3n+1

Ta thấy 3^3n là số lẻ

=> 3^3n+1 là số chẵn

=> Trong dãy số tự nhiên chỉ có số 2 là số nguyên tố thôi

mà n>1

=> 3^3n+1 không thể là 2

=> 3^3n+1 là hợp số 

k cho mik nha!!!!!!!!!!!!!!