a) 67+135+33

= ( 67+33)+135

= 100 + 135

= 235

b) 146+121+54+379

= ( 146+54)+( 121+379)

= 200 + 500

= 700

c) 198+232-98-32

= ( 232-32)+(198-98)

= 200 + 100

= 300

d)1+2+3+4+.........+50

= ( 50+1) x 50:2 =1275

e)2+4+6+8+..........+100

= ( 100+2) x 50 : 2 =2550

f) 23 x 56 +56

= 1288 + 56

= 1344

g)32 x 19+32

= 608 + 32

= 640

\(a.67+135+33\)

\(=\left(67+33\right)+135\)

\(=100+135=235\)  

\(b.141+121+54+379\)

\(=\left(146+54\right)+\left(121+379\right)\)

\(=200+500=700\)

\(c.198+232-98-32\)

\(=\left(232-32\right)+\left(198-98\right)\)

\(=200+100=300\)

\(f.23.56+56=1288+56=1344\)

\(g.32.19+32=608+32=640\)

23.17-23.14

=23.(17-14)

=23.3 = 69

23.(17-14)=23.3=69

Bài 5: 

a: BC=10cm

b: HA=4,8cm

HB=3,6(cm)

HC=6,4(cm)

Bài 6:

\(x^3=6+3\sqrt[3]{\left(3+2\sqrt{2}\right)\left(3-2\sqrt{2}\right)}\left(\sqrt[3]{3+2\sqrt{2}}+\sqrt[3]{3-2\sqrt{2}}\right)\\ \Leftrightarrow x^3=6+3x\sqrt[3]{1}\\ \Leftrightarrow x^3-3x=6\\ y^3=34+3\sqrt[3]{\left(17+12\sqrt{2}\right)\left(17-12\sqrt{2}\right)}\left(\sqrt[3]{17+12\sqrt{2}}+\sqrt[3]{17-12\sqrt{2}}\right)\\ \Leftrightarrow y^3=34+3y\sqrt[3]{1}\\ \Leftrightarrow y^3-3y=34\\ \Leftrightarrow P=x^3-3x+y^3-3y+1980=6+34+1980=2020\)

gfrưerrrrrrrrrrr

mình làm những bài bn chưa lm nhé

9B

10A

bài 2

have repainted

bàii 3

ride - walikking

swimming

watch

2 have repainted

4 have done 

8 have stepped

9 have you ever played

7) 1 riding -walking

2 swimming

3 watching

8)

2 my mother doesn't like listening to music

5 doing more exercises makes you healthier

còn lại ok nha

chịu ???????????????????

\(3x=4z\Rightarrow\dfrac{x}{4}=\dfrac{z}{3}\); \(\dfrac{x}{5}=\dfrac{y}{6}\)

\(\Rightarrow\dfrac{x}{20}=\dfrac{z}{15}=\dfrac{y}{24}\)

\(\Rightarrow\dfrac{x}{20}=\dfrac{z}{15}=\dfrac{y}{24}=\dfrac{x-y+z}{20-24+15}=\dfrac{121}{11}=11\)

\(\Rightarrow x=20.11=220;z=15.11=165;y=264\)

lèm bài mấy zị

làm hết à  :v

Bài 2:

Ta có:\(2\sqrt{48}< 2\sqrt{49}\) ; 

         \(3\sqrt{27}>3\sqrt{25}\)

mà \(2\sqrt{49}< 3\sqrt{25}\left(14< 15\right)\)

\(\Rightarrow3\sqrt{27}>3\sqrt{25}>2\sqrt{49}>2\sqrt{48}\)

\(\Rightarrow3\sqrt{27}>2\sqrt{48}\)

b)

Ta có:\(\sqrt{50}+\sqrt{2}>\sqrt{49}+\sqrt{1}\) 

        \(\sqrt{50+2}< \sqrt{64}\)

mà \(\sqrt{49}+\sqrt{1}=\sqrt{64}\left(8=8\right)\)

\(\Rightarrow\sqrt{50}+\sqrt{2}>8>\sqrt{50+2}\)

\(\Rightarrow\sqrt{50}+\sqrt{2}>\sqrt{50+2}\)

Bài 2

5 C

Bài 3

1 D

6 C

Còn lại ol r nhé

2) 5. C

3) 2. D

6. C

Còn lại ok nha

Câu 5: 

a: Xét ΔABC có \(BC^2=AB^2+AC^2\)

nên ΔABC vuông tại A

c: Xét tứ giác AEDF có 

\(\widehat{EAF}=\widehat{AFD}=\widehat{AED}=90^0\)

Do đó: AEDF là hình chữ nhật

mà AD là tia phân giác của \(\widehat{FAE}\)

nên AEDF là hình vuông

a: \(=5x^2-10x-5x^2+7x=-3x\)

b: \(=2x^3+3xy^2-4y-3xy^2=2x^3-4y\)