Lời giải:
a. $(d)$ cắt trục tung tại điểm có tung độ $3$, tức là cắt trục tung tại điểm $(0;3)$

$(0;3)\in (d)$

$\Leftrightarrow 3=(m+2).0+2m^2+1$

$\Leftrightarrow 2m^2=2$
$\Leftrightarrow m^2=1$

$\Leftrightarrow m=\pm 1$

Khi $m=1$ thì ta có hàm số $y=3x+3$

Khi $m=-1$ thì ta có hàm số $y=x+3$ 

Bạn có thể tự vẽ 2 đths này.

b.

Để $(d)$ cắt $(d')$ thì: $m+2\neq 2m+2$

$\Leftrightarrow m\neq 0$

Lời giải:

b/

\(\sqrt{52-16\sqrt{3}}+\sqrt{(4\sqrt{3}-7)^2}=\sqrt{48+4-2\sqrt{48.4}}+|4\sqrt{3}-7|\)

\(=\sqrt{(4\sqrt{3}-2)^2}+|4\sqrt{3}-7|\\ =|4\sqrt{3}-2|+|4\sqrt{3}-7|\\ =4\sqrt{3}-2+7-4\sqrt{3}=5\)

c/

\(=\frac{\sqrt{10}+3}{(\sqrt{10}-3)(\sqrt{10}+3)}-\frac{\sqrt{10}(\sqrt{5}+\sqrt{2})}{\sqrt{5}+\sqrt{2}}\\ =\sqrt{10}+3-\sqrt{10}=3\)

a ) Ta có : AB , AC là tiếp tuyến của (O) 

$\Rightarrow AB\perp OB,AC\perp OC$

$\Rightarrow \widehat{ABO}+\widehat{ACO}={90}^0+{90}^0={180}^0\Rightarrow ABOC$ nội tiếp 

b ) Vì AB là tiếp tuyến của (O) 

$\Rightarrow \widehat{ABE}=\widehat{ADB}\Rightarrow \Delta ABE\sim \Delta ADB\left(g.g\right)$

$\Rightarrow \frac{AB}{AD}=\frac{AE}{AB}\Rightarrow A{B}^2=AE.AD$

c ) Ta có :  là tiếp tuyến của (O) $\Rightarrow \widehat{ACE}=\widehat{EBC}$

Mà BD // AC $\Rightarrow \widehat{ECB}=\widehat{EDB}=\widehat{ADB}=\widehat{EAC}$

$\Rightarrow \Delta EAC\sim \Delta ECB\left(g.g\right)\Rightarrow \widehat{CEA}=\widehat{CEB}$

d ) Gọi $CO\cap BD=F$

Vì BD // AC , $OC\perp AC\Rightarrow CF\perp BD$

$\Rightarrow d\left(AC,BD\right)=CF$Vì AO = 3R , $OB=R\Rightarrow AB=\sqrt{O{A}^2-O{B}^2}=2\sqrt{2}R$$\Rightarrow \frac{1}{2}BC.AO=AB.OC\left(=2S_{ABOC}\right)$$\Rightarrow BC=\frac{4\sqrt{2}R}{3}$ Ta có : $\widehat{BAO}=\widehat{BCO}\Rightarrow \Delta ABO\sim \Delta CFB\left(g.g\right)$$\Rightarrow \frac{AB}{CF}=\frac{AO}{CB}=\frac{BO}{BF}$$\Rightarrow \frac{2\sqrt{2}R}{CF}=\frac{3R}{\frac{4\sqrt{2}R}{3}}$$\Rightarrow CF=\frac{16R}{9}$

Dear Lvamy,

I think you need to know about Tet and I also need, So, read it:

Vietnam is a country famous for its several holidays and festivals, especially Tet holiday. It takes place from the first day in the lunar calendar until the third day. Though occurring in a short period of time, Tet is believed to be the most significant and popular holiday in Vietnam. There are many special foods to prepare for Tet meals such as: banh chung, Vietnamese sausage, sticky rice and spring rolls. The food is thought to reflect Vietnamese people’s habit and custom as well as Vietnamese’s lifestyle. Besides, the meal has a variety of dishes such as fish, vegetable to show the hope for a lucky and prosperous new year. In terms of customs, children receiving red envelopes of money from the elderly and people visiting their relative’s houses and going to church are popular activities. Giving lucky money is believed to be able to bring children hope and health in the next year. Church and pagoda are the symbols of peace; therefore, individuals go there and pray for a lucky year. Traditionally, the house is decorated with peach flowers in the North and Ochna integerrima in the southern part of Vietnam. Moreover, the house as well as town are clear, decorative and beautiful as all of them are ready to start a new year. People have a cozy atmosphere and enjoy a happy time with their family’s members. It’s high time for people living in different parts of the country to gather and spend time together. Tet is an opportunity for everyone to come back home after much stress and pressure of studying and working. Tet is not just a holiday, it is a culture and habit of Vietnamese since its deep meaning is sacred and significant. In short, Tet includes not only happiness but also long-standing events in people’s souls.

Thank you for reading! A great and happy Tet!

                                                                                       Ha An

Dear Lvamy,

I think you need to know about Tet and I also need, So, read it:

Vietnam is a country famous for its several holidays and festivals, especially Tet holiday. It takes place from the first day in the lunar calendar until the third day. Though occurring in a short period of time, Tet is believed to be the most significant and popular holiday in Vietnam. There are many special foods to prepare for Tet meals such as: banh chung, Vietnamese sausage, sticky rice and spring rolls. The food is thought to reflect Vietnamese people’s habit and custom as well as Vietnamese’s lifestyle. Besides, the meal has a variety of dishes such as fish, vegetable to show the hope for a lucky and prosperous new year. In terms of customs, children receiving red envelopes of money from the elderly and people visiting their relative’s houses and going to church are popular activities. Giving lucky money is believed to be able to bring children hope and health in the next year. Church and pagoda are the symbols of peace; therefore, individuals go there and pray for a lucky year. Traditionally, the house is decorated with peach flowers in the North and Ochna integerrima in the southern part of Vietnam. Moreover, the house as well as town are clear, decorative and beautiful as all of them are ready to start a new year. People have a cozy atmosphere and enjoy a happy time with their family’s members. It’s high time for people living in different parts of the country to gather and spend time together. Tet is an opportunity for everyone to come back home after much stress and pressure of studying and working. Tet is not just a holiday, it is a culture and habit of Vietnamese since its deep meaning is sacred and significant. In short, Tet includes not only happiness but also long-standing events in people’s souls.

Thank you for reading! A great and happy Tet!

                                                                                       Ha An

không

Em sẽ ngăn các bạn ấy lại

Em không đồng tình với ý kiến trên vì: Chúng ta phải có tính tự lập, tự giác làm bài, không nên gian lận thi cử như vậy.

Nếu là bạn của Bình và Hân em sẽ khuyên hai bạn sẽ không làm vậy nữa, bài của người người đấy làm, không ỷ lại vào người khác.

Bạn kiểm tra lại xem đã viết đúng đề chưa vậy?