Giải dùm mình vs mình đang gấp ạ
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\(\Leftrightarrow n^5+n^2-n^2+1⋮n^3+1\)
\(\Leftrightarrow-n^3+n⋮n^3+1\)
\(\Leftrightarrow n=1\)
One of the biggest environmental impacts of human activities is air pollution
\(a.Fe+2HCl\rightarrow FeCl_2+H_2\\ b.n_{Fe}=0,15\left(mol\right)\\ n_{HCl\left(pứ\right)}=2n_{Fe}=0,3\left(mol\right)\\ \Rightarrow m_{HCl\left(pứ\right)}=0,3.36,5=10,95\left(g\right)\\ \Rightarrow m_{ddHClpu}=\dfrac{10,95}{10,95\%}=100\left(g\right)\\ Dùngdư10gddHCl\\ \Rightarrow m_{HCl\left(bđ\right)}=\left(100+10\right).10,95\%=12,045\left(g\right)\\ c.n_{H_2}=n_{FeCl_2}=n_{Fe}=0,15\left(mol\right)\\ m_{ddsaupu}=8,4+110-0,15.2=118,1\left(g\right)\\ C\%_{FeCl_2}=\dfrac{0,15.127}{118,1}.100=16,13\%\)
1) \(A=25x^2+10x+1\)
\(A=5x^2+2.5.10x+1\)
\(A=5x^2+100x+1\)
\(A=\left(5x+1\right)^2\)
Thay \(x=\dfrac{1}{5}\) vào biểu thức \(\left(5x+1\right)^2\)
\(\left(5x+1\right)^2\)
= \(\left(5.\dfrac{1}{5}+1\right)^2\)
= \(2^2=4\)
Nếu sai thì cho mình xin lỗi nhé
2) Bài này mình không biết làm
a: Ta có: \(5-3x< 8\)
\(\Leftrightarrow3x>-3\)
hay x>-1
b: Ta có: \(\dfrac{2x-5}{4}\ge\dfrac{3-x}{3}\)
\(\Leftrightarrow3\left(2x-5\right)\ge4\left(3-x\right)\)
\(\Leftrightarrow6x-15\ge12-4x\)
\(\Leftrightarrow10x\ge27\)
hay \(x\ge\dfrac{27}{10}\)
c: Ta có: \(2x+5< x+7\)
\(\Leftrightarrow2x-x< 7-5\)
hay x<2
d: Ta có: \(4\left(x-3\right)\ge x+2\)
\(\Leftrightarrow4x-12-x-2\ge0\)
\(\Leftrightarrow3x\ge14\)
hay \(x\ge\dfrac{14}{3}\)
e: Ta có: \(\dfrac{2x+2}{3}< 2+\dfrac{x-2}{2}\)
\(\Leftrightarrow4x+4< 12+3x-6\)
\(\Leftrightarrow4x-3x< 6-4\)
hay x<2
f: Ta có: \(x-\dfrac{5x+2}{6}>\dfrac{7-3x}{4}\)
\(\Leftrightarrow12x-2\left(5x+2\right)>3\left(7-3x\right)\)
\(\Leftrightarrow2x-4>21-9x\)
\(\Leftrightarrow11x>25\)
hay \(x>\dfrac{25}{11}\)