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25 tháng 9 2021

Câu 1:

\(A=10\sqrt{0,01}-\sqrt{\dfrac{9}{16}}+3\sqrt{49}-\dfrac{1}{6}\sqrt{4}\)

\(=10.\dfrac{1}{10}-\dfrac{3}{4}+3.7-\dfrac{1}{6}.2\)

\(=1-\dfrac{3}{4}+21-\dfrac{1}{3}=\dfrac{251}{12}\)

Câu 2:

Do \(\left|x+2\right|,\left|2y+3\right|\ge0\)

\(\Rightarrow\left\{{}\begin{matrix}x+2=0\\2y+3=0\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}x=-2\\y=-\dfrac{3}{2}\end{matrix}\right.\)

10 tháng 1 2022

a/ Tam giác AMN cân tại A (gt). \(\Rightarrow\) \(\widehat{AMN}=\widehat{ANM};AM=AN.\)

Xét tam giác AMB và tam giác ANC có:

+ AM = AN (cmt).

\(\widehat{AMB}=\widehat{ANC}\left(\widehat{AMN}=\widehat{ANM}\right).\)

+ MB = NC (gt).

\(\Rightarrow\) Tam giác AMB = Tam giác ANC (c - g - c).

\(\Rightarrow\) AB = AC (cặp cạnh tương ứng).

Xét tam giác ABC có: AB = AC (cmt).

\(\Rightarrow\) Tam giác ABC cân tại A.

b/ Tam giác ABC cân tại A (cmt) \(\Rightarrow\) \(\widehat{ABC}=\widehat{ACB}.\)

Mà \(\widehat{ABC}=\widehat{MBH;}\widehat{ACB}=\widehat{NCK}\text{​​}\) (đối đỉnh).

\(\Rightarrow\) \(\widehat{MBH}=\widehat{NCK}.\)

Xét tam giác MBH và tam giác NCK \(\left(\widehat{BHM}=\widehat{CKN}=90^o\right)\)có:

+ MB = NC (gt).

\(\widehat{MBH}=\widehat{NCK}\left(cmt\right).\)

\(\Rightarrow\) Tam giác MBH = Tam giác NCK (cạnh huyền - góc nhọn).

c/ Tam giác MBH = Tam giác NCK (cmt).

\(\Rightarrow\) \(\widehat{BMH}=\widehat{CNK}\) (cặp góc tương ứng).

Xét tam giác OMN có: \(\widehat{NMO}=\widehat{MNO}\) (do \(\widehat{BMH}=\widehat{CNK}\)).

\(\Rightarrow\) Tam giác OMN tại O.

 

27 tháng 12 2021

The doctor (already, examine)____________________ the patient.

Marconi (invent)________________ the telephone.

How many French tourists (meet)_______ she __________ last weekend?

They (repair)________________ their house all this month.

You (work)______________ too hard! That’s why you are tired.

When the doorbell (ring)_________, I (get)______ up and (answer)________it.

We (know)______________ her for years.

Her parents (live)__________ in Hue from 1985 to 1996.

The plant I bought (grow)______________ very much. And I water it every day.

We (meet)_________________ at 10 o’clock tonight.

Kate looks much thinner. She (lose)_____________ a lot of weight.

Look at those black clouds! It (rain)______________________.

Look! The fire engine (arrive)_________________.

Run! The bus driver (wait)_________________ for us!

Watch the baby! He (fall)__________________ off the bed.

Look at the sun! It (be)__________________ a very hot day!

It’s 7:30 in the morning and Mr. Brown (drive)_______________ to work, as usual.

Hurry up! We (miss)______________________ the train.

I (brush)_____________________ my teeth, have a wash and go to bed.

I (not have)_________________ breakfast this morning.

14 tháng 11 2021

Câu 2: 

#include <bits/stdc++.h>

using namespace std;

long long n,i,x,nn;

int main()

{

cin>>n>>x;

nn=x;

for (i=2; i<=n; i++)

{

cin>>x;

nn=min(nn,x);

}

cout<<nn;

return 0;

}

e) \(20\%\cdot1\dfrac{1}{4}\cdot12\cdot\dfrac{25}{45}\cdot0,6\)

\(=\dfrac{1}{5}\cdot\dfrac{5}{4}\cdot\dfrac{12}{1}\cdot\dfrac{5}{9}\cdot\dfrac{6}{10}\)

\(=1\)