1 is bigger than mine

2 the tallest student in my class

3 speaks English better than Mum

4 cook as well as lan

5 the best in the city

6 is better than this one

7 is a more careful writer than she is

8 drives more carefully than Peter

1. Your kitchen is bigger than mine

2. Dave is the tallest person in the class

3. Dad speaks English better than Mum

4. Hoa can't cook as well as Lan

5. This restaurant ts the best one in the city

6. That watch is better than this one

7. My sister doesn't write more carelessly than she did

8. Tom drives more carefully than Peter

Câu 7 ko chắc đâu nha

1. didn’t use to be

2.used to write

3. used to play

4. didn’t use to travel

5. used to walk

6. didn’t use to swim

7. used to watch

8. used to climb

9. didn’t use to buy

10. used to shop

Ta có: \(\frac{1}{5}+\frac{1}{6}+...+\frac{1}{17}\)

\(=\left(\frac{1}{5}+\frac{1}{6}+...+\frac{1}{10}\right)+\left(\frac{1}{11}+...+\frac{1}{17}\right)\)

\(< \frac{1}{5}.6+\frac{1}{11}.6=\frac{5}{6}+\frac{6}{11}=\frac{101}{55}< 2\)

Đặt A=1/3+2/3^2+...+100/3^100
=>3A=1+2/3+...+100/2^99
=>3A-A=1+(2/3-1/3)+(3/3²-2/3²)+...(100/2⁹⁹-99/2^99)-100/3¹⁰⁰

=>2A=1+1/3+1/3+1/3²+...+1/3⁹⁹-100/3¹⁰⁰

Ta lại đặt tiếp B=1/3+...+1/3⁹⁹

tiếp tục làm 3B=1+...+1/3⁹⁸

=>3B-B=1+...+1/3^98-1/3+...+1/3⁹⁹=1-1/3^99

=>B=(1-1/3^99)/2 (đến đây viết mũ là ^ vì lười)

đến đây ta có 2A=1+(1-1/3^99)/2 -100/3^100

=(3^100-100)/3^100 +(1-1/3^99)/2

quy đồng lên nó thành

2A=2x3^100-200/3^100x2 +(3^99-1)/3^99x2

2A=(2x3^100-200+3^100-3)/3^100x2

     =(3^101-203)/3^100x2

     ta c/m 2a<3/2 là ok

*nhân chéo lên =>2(3^101-203)<3^101x2

đồng nghĩa với 2x3^101 -406<3^101x2 (điều này luôn đúng)

=>bài toán đc chứng minh

Trong \(\Delta ABC\) có:

\(BC^2=AC^2+AB^2=144+25=169\)

\(\Rightarrow BC=13\left(cm\right)\)

Xét \(\Delta\)ABC có:

MA = MB (gt)

NA=NC (gt)

=> MN là đường trung bình \(\Delta ABC\)

=>\(MN=\dfrac{1}{2}BC=\dfrac{1}{2}.13=6,5\left(cm\right)\)

Lại có: \(AN=\dfrac{1}{2}AC=6\left(cm\right)\)

P/S sai thui :))

chết mịa roài N là trung điểm BC :)) hèn gì thầy lạ :D sorry chán quá chắc 30phut nữa có thằng nhóc láu cá nó vào ns liền rồi nó giải cho :D

bạn làm như thế này:

65 * x + 35 * x = 6000 = (65 +35) * x

                                    =   100 * x

                                    =    100 * x = 6000

                                    =  6000 : 100 

                                    = 60 nha