\(\Rightarrow\left[{}\begin{matrix}x+2=0\\x-4=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=-2\\x=4\end{matrix}\right.\)

\(a,4P+5O_2\xrightarrow{t^o}2P_2O_5\\ 4:5:2\\ b,2Fe+3Cl_2\xrightarrow{t^o}2FeCl_3\\ 2:3:2\\ c,Fe_2O_3+6HNO_3\to 2Fe(NO_3)_3+3H_2O\\ 1:6:2:3\\ d,C_2H_4+3O_2\xrightarrow{t^o}2CO_2+2H_2O\\ 1:3:2:2\)

\(a,n_C=\dfrac{4}{12}=0,33(mol)\\ n_{H_2O}=\dfrac{3,6}{18}=0,2(mol)\\ n_{O_2}=\dfrac{4,48}{22,4}=0,2(mol)\\ b,m_{SO_2}=1,25.64=80(g)\\ V_{SO_2}=1,25.22,4=28(l)\\ m_{NH_3}=17.1,25=21,25(g)\\ V_{NH_3}=22,4.1,25=28(l)\)

\(a,f\left(3\right)=3+1=4\\ f\left(-3\right)=3+1=4\\ b,y=f\left(x\right)=\left|x\right|+1\)

\(\Leftrightarrow\left(x-3\right)^2=\dfrac{1}{121}\\ \Leftrightarrow\left[{}\begin{matrix}x-3=\dfrac{1}{11}\\3-x=\dfrac{1}{11}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{34}{11}\\x=\dfrac{32}{11}\end{matrix}\right.\)

\(a,\Leftrightarrow x^3+3x^2+5x+a=\left(x+3\right).a\left(x\right)\)

Thay \(x=-3\Leftrightarrow-27+27-15+a=0\Leftrightarrow a=15\)

\(b,\Leftrightarrow-3x^3+5x^2-9x+a=\left(-3x+5\right).b\left(x\right)\)

Thay \(x=\dfrac{5}{3}\Leftrightarrow-\dfrac{125}{9}+\dfrac{125}{9}-15+a=0\Leftrightarrow a=15\)

\(c,\Leftrightarrow x^4+3x^3-x^2+ax+b=\left(x^2+2x-3\right).c\left(x\right)=\left(x+3\right)\left(x-1\right).c\left(x\right)\)

Thay \(x=-3\Leftrightarrow81-81-9-3a+b=0\Leftrightarrow3a-b=-9\left(1\right)\)

Thay \(x=1\Leftrightarrow1+3-1+a+b=0\Leftrightarrow a+b=-3\left(2\right)\)

\(\left(1\right)\left(2\right)\Leftrightarrow\left\{{}\begin{matrix}a=-3\\b=0\end{matrix}\right.\\ d,\Leftrightarrow x^3+3x^2-2x+a=\left(x+2\right).d\left(x\right)+5\)

Thay \(x=-2\Leftrightarrow-8+12+4+a=5\Leftrightarrow a=-3\)

\(a,\Rightarrow\dfrac{-25}{30}\le\dfrac{x}{30}\le\dfrac{-24}{30}\Rightarrow x\in\left\{-25;-24\right\}\\ b,\Rightarrow\dfrac{19}{150}< \dfrac{x}{150}< \dfrac{11}{75}=\dfrac{22}{150}\\ \Rightarrow x\in\left\{20;21\right\}\)

Ta có \(y^2=3-2\left|2x+3\right|\ge0\Leftrightarrow0\le\left|2x+3\right|\le\dfrac{3}{2}\)

Mà \(x,y\in Z\Leftrightarrow\left|2x+3\right|\in\left\{0;1\right\}\)

Với \(\left|2x+3\right|=0\Leftrightarrow x=-\dfrac{3}{2}\left(loại\right)\)

Với \(\left|2x+3\right|=1\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=-2\end{matrix}\right.\Leftrightarrow y^2=1\Leftrightarrow\left[{}\begin{matrix}y=1\\y=-1\end{matrix}\right.\)

Vậy PT có nghiệm \(\left(x;y\right)\) là \(\left(-1;1\right);\left(-1;-1\right);\left(-2;1\right);\left(-2;-1\right)\)

\(a,n_{H_2}=\dfrac{3,36}{22,4}=0,15(mol)\\ PTHH:Fe+2HCl\to FeCl_2+H_2\\ \Rightarrow n_{Fe}=n_{H_2}=0,15(mol)\\ \Rightarrow m_{Fe}=0,15.56=8,4(g)\\ \Rightarrow \%_{Fe}=\dfrac{8,4}{15}.100\%=56\%\\ \Rightarrow \%_{Cu}=100\%-56\%=44\%\\ b,n_{HCl}=2n_{H_2}=0,3(mol)\\ \Rightarrow C_{M_{HCl}}=\dfrac{0,3}{0,1}=3M\)

Số lớn là \(\left(998+100\right):2=549\)

Số bé là \(549-100=449\)