\(a) OM \)\(><\)\(ON;OM\) \(><\) \(Oy;Ox\)\(><\) \(ON;Ox\) \(><\) \(Oy\)

\(b) ON ≡ Oy ; OM ≡ Ox\)

\(c) MN \)\(>< \) \(Ny\) . Không 

\(a)\) Tia đối nhau gốc \(A\) là: \(AO\)\(><\)\(Ax\),\(AB\)\(><\)\(Ax\),\(Ay\)\(><\)\(Ax\)

\(b) \)Tia gốc \(O \) trùng nhau là :  \(OA≡Ox ; OB ≡ Oy\)

\(c) OB = AB + AO \)

\Rightarrow  \(OB = 7+3,4 = 10,4 cm \)

\(1.\) Travel by flying cars/ 2080.

\rightarrow  Travelling by flying cars will be in 2080

\(2.\) Sky traffic/ more popular than road traffic.

\rightarrow Sky traffic will be more popular than road traffic.

Thay \(x=1;y=-4 \) vào biểu thức \(A=( -\dfrac{1}{16}x^2y^2 ) . 4x^3 \) ta đc :

\Rightarrow \(A=( -\dfrac{1}{16}x^2y^2 ) . 4x^3 \)\(=A = ( -\dfrac{1}{16} .16 ) . 4 =-4\)

\(m_KCl(tan)= (34.150)/100= 51(g)\)

What is there on the walls of the classroom ?

Dịch : Cái gì ở trên tường trong lớp hc ? 

\(C\%ddKCl=\)\(\dfrac{20}{380+20}. 100 = 5\)\(\%\)

\(C\%ddKCl\)\(= \dfrac{20}{500} .100% = 4%\)\(\%\)=4\(\%\)

\(∑m_{dd}= m_{NaCl} + m_{H_2O} = 15 + 45 = 60(gam)\)

\(\text{C%}ddNaCl=\)\(\dfrac{15}{60}.100\%=25\%\)

\(NaCl+AgNO_3\rightarrow NaNO_3+AgCl↓ \)

\(Theo PT p.ư : n_{NaCl}=n_{AgCl↓} = 0,9 (mol) \)

\(\rightarrow m_{NaCl} =0,9.58,5=52,65(g) \)

\(dd_{NaCl} có : \dfrac{250.36}{136}=66,2(g)>52,65(g) \)

\(\rightarrow :\) dd chưa bão hòa