\(10+2\sqrt{21}\)

b)  

K
Khách

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NM
6 tháng 10 2021

ta có :

undefined

6 tháng 10 2021

Hay quá, Minh Quang không bị lừa :)))

7 tháng 10 2021

a) 10+2\(\sqrt{21}\)= 3+7 +2\(\sqrt{3.7}\) =3+2\(\sqrt{3.7}\) +7= (\(\sqrt{3}\) +\(\sqrt{7}\))2 

b) 12-2\(\sqrt{27}\) = 9+3-2\(\sqrt{9.3}\) =9-2\(\sqrt{9.3}\) +3=(\(\sqrt{9}\)-\(\sqrt{3}\))2

c) 11+2\(\sqrt{30}\) =6+5+2\(\sqrt{6.5}\) = 6+2\(\sqrt{6.5}\) +5=(\(\sqrt{6}\) +\(\sqrt{5}\) )2

d) 14- 2\(\sqrt{45}\)= 9+5-2\(\sqrt{9.5}\) =9-2\(\sqrt{9.5}\) +5= (\(\sqrt{9}\) -\(\sqrt{5}\) )2

7 tháng 10 2021

a) \(10+2\sqrt{21}=2\left(5+\sqrt{21}\right)\)

b)\(12-2\sqrt{27}=12-2.3\sqrt{3}=12-6\sqrt{3}=6\left(6-\sqrt{3}\right)\)

c)\(11+2\sqrt{30}=10+2\sqrt{30}+1=\left(\sqrt{10}+1\right)^2\)

d)\(14-2\sqrt{45}=9-2\sqrt{9.5}+5=\left(3-\sqrt{5}\right)^2\)

7 tháng 10 2021

a) (\(\sqrt{7}+\sqrt{3}\))2

b) ( \(\sqrt{9}-\sqrt{3}\))2

c) (\(\sqrt{6}+\sqrt{5}\))2

d) (\(\sqrt{9}-\sqrt{5}\))2

7 tháng 10 2021

a/ 2(5+\(\sqrt{21}\))

b/ 2(6-\(\sqrt{27}\))

c/(\(\sqrt{5}\)+\(\sqrt{6}\))^2

d/2(7-\(45\))

7 tháng 10 2021

\(\left(\sqrt{ }7+\sqrt{ }3\right)^2\)

\(\left(\sqrt{ }9-\sqrt{ }3\right)^2\)

\(\left(\sqrt{ }5+\sqrt{ }6\right)^2\)

\(\left(\sqrt{ }9-\sqrt{ }5\right)^2\)

7 tháng 10 2021

a)\(\left(\sqrt{7}+\sqrt{3}\right)^2\)

b)\(\left(\sqrt{9}-\sqrt{3}\right)^2\)

c)\(\left(\sqrt{5}+\sqrt{6}\right)^2\)

d)\(\left(\sqrt{9}-\sqrt{5}\right)^2\)

7 tháng 10 2021

a) \(\left(\sqrt{3}+\sqrt{7}\right)^2\)
b) \(\left(\sqrt{3}-\sqrt{9}\right)^2\)
c) \(\left(\sqrt{5}+\sqrt{6}\right)^2\)
d) \(\left(\sqrt{9}-\sqrt{5}\right)^2\)
 

7 tháng 10 2021

a) (\(\sqrt{7}+\sqrt{3}\))2
b) (\(\sqrt{9}-\sqrt{3}\))2
c) (\(\sqrt{6}+\sqrt{5}\))2
d) (\(\sqrt{9}-\sqrt{5}\))2

7 tháng 10 2021

a) \(\left(\sqrt{3}+\sqrt{7}\right)^2\)

b) \(\left(\sqrt{3}+\sqrt{9}\right)^2\)

c) \(\left(\sqrt{5}+\sqrt{6}\right)^2\)

d)\(\left(\sqrt{9}+\sqrt{5}\right)^2\)

7 tháng 10 2021

a, 2(5+\(\sqrt{21}\))

7 tháng 10 2021

a) \(\left(\sqrt{3}+\sqrt{7}\right)^2\)

b) \(\left(\sqrt{9}-\sqrt{3}\right)^2\)

c) \(\left(\sqrt{5}+\sqrt{6}\right)^2\)

d) \(\left(\sqrt{9}-\sqrt{5}\right)^2\)

8 tháng 10 2021

a. 10+ 2\(\sqrt{21}\)= 3+ \(2\sqrt{3}.\sqrt{7}\)+7 =(\(\sqrt{3}+\sqrt{7}\))\(^2\)
b. 12- 2\(\sqrt{27}\)= 9- \(2.\sqrt{9}.\sqrt{3}\)= (3-\(\sqrt{3}\))\(^2\)
c. 11+ 2\(\sqrt{30}\)= 5+ 2\(\sqrt{5}.\sqrt{6}\)+ 6= (\(\sqrt{5}+\sqrt{6}\))\(^2\)
d. 14- 2\(\sqrt{45}\)= 9- 2\(\sqrt{9}.\sqrt{5}\)+ 5= (3- \(\sqrt{5}\))\(^2\)

8 tháng 10 2021

loading...

 

 

9 tháng 10 2021

Mở ảnh

10 tháng 10 2021

a) 10 + 2\(\sqrt{21}\)=\(\left(\sqrt{7}+\sqrt{3}\right)^2\)

b) 12 - 2\(\sqrt{27}\)=\(3\times\left(\sqrt{3}-1\right)^2\)

c) 11 + 2\(\sqrt{30}\)=\(\left(\sqrt{5}+\sqrt{6}\right)^2\)

d) 14 - 2\(\sqrt{45}\)=\(\left(3-\sqrt{5}\right)^2\)

11 tháng 10 2021

a)\(10+2\sqrt{21}=\left(\sqrt{3}+\sqrt{7}\right)^2\)

b)\(12-2\sqrt{27}=\left(\sqrt{3}-3\right)^2\)

c)\(11+2\sqrt{30}=\left(\sqrt{5}+\sqrt{6}\right)^2\)

d)\(14-2\sqrt{45}=\left(3-\sqrt{5}\right)^2\)

11 tháng 10 2021

loading...

 

12 tháng 10 2021

a)  10+2\sqrt{21}=\left(\sqrt{3}+\sqrt{7}\right)^210+221=(3+7)2

b)  12-2\sqrt{27}=\left(3-\sqrt{3}\right)^212227=(33)2

c)  11+2\sqrt{30}=\left(\sqrt{5}+\sqrt{6}\right)^211+230=(5+6)2

d)  14-2\sqrt{45}=\left(3-\sqrt{5}\right)^214245=(35)2

12 tháng 10 2021

a) \(\left(\sqrt{7}+\sqrt{3}\right)^2\)

b) \(\left(3-\sqrt{3}\right)^2\)

c) \(\left(\sqrt{6}+\sqrt{5}\right)^2\)

d) \(\left(3-\sqrt{5}\right)^{^{ }2}\)

16 tháng 10 2021

a)\(\left(\sqrt{3}+\sqrt{7}\right)^2\)

b)\(\left(3-\sqrt{3}\right)^2\)

c)\(\left(\sqrt{5}+\sqrt{6}\right)^2\)

d)\(\left(3-\sqrt{5}\right)^2\)

16 tháng 10 2021

a) \(\left(\sqrt{3}+\sqrt{7}\right)^2\)

b) \(\left(3-\sqrt{3}\right)^2\)

c) \(\left(\sqrt{5}+\sqrt{6}\right)^2\)

d) \(\left(3-\sqrt{5}\right)^2\)

20 tháng 10 2021

a) \(10+2\sqrt{21}=3+2\sqrt{3.7}+7=\left(\sqrt{3}\right)^2+2\sqrt{3}.\sqrt{7}+\left(\sqrt{7}\right)^2=\left(\sqrt{3}+\sqrt{7}\right)^2\)

b) \(12-2\sqrt{27}=9-2\sqrt{3.9}+3=3^2-2.3.\sqrt{3}+\left(\sqrt{3}\right)^2=\left(3-\sqrt{3}\right)^2\)

c) \(11+2\sqrt{30}=6+2\sqrt{6.5}+5=\left(\sqrt{6}\right)^2+2\sqrt{6}.\sqrt{5}+\left(\sqrt{5}\right)^2=\left(\sqrt{6}+\sqrt{5}\right)^2\)

d) \(14-2\sqrt{45}=9-2\sqrt[]{9.5}+5=3^2-2.3\sqrt{5}+\left(\sqrt{5}\right)^2=\left(3-\sqrt{5}\right)^2\)

27 tháng 10 2021

a) 10+2\(\sqrt{21}\) = (\(\sqrt{7}\))2+(\(\sqrt{3}\))2+2\(\sqrt{7}\).\(\sqrt{3}\) = (\(\sqrt{7}\))2+ 2\(\sqrt{7}\).\(\sqrt{3}\)+(\(\sqrt{3}\)) 2 = (\(\sqrt{7}\)+\(\sqrt{3}\))2

b) 12-2\(\sqrt{27}\) = 32+(\(\sqrt{3}\))2-2\(\sqrt{9}\).\(\sqrt{3}\) = 32-2\(\sqrt{9}\).\(\sqrt{3}\)+(\(\sqrt{3}\))2 = (\(\sqrt{9}\)-\(\sqrt{3}\))2

c) 11+2\(\sqrt{30}\) = (\(\sqrt{6}\))2+(\(\sqrt{5}\))2+2\(\sqrt{6}\).\(\sqrt{5}\) = (\(\sqrt{6}\)+\(\sqrt{5}\))2

d) 14-2\(\sqrt{45}\) = 32+(\(\sqrt{5}\))2-2\(\sqrt{9}\).\(\sqrt{5}\) = (\(\sqrt{9}\)-\(\sqrt{5}\))2

27 tháng 10 2021

a) \(10+2\sqrt{21}\)  

\(=3+2\sqrt{3\times7}+7\) 

\(=\left(\sqrt{3}\right)^2+2\sqrt{3\times7}+\left(\sqrt{9}\right)^2\) 

\(=\left(\sqrt{3}+\sqrt{7}\right)^2\) 

b) \(12-2\sqrt{27}\)

\(=9-2\sqrt{9\times3}+3\) 

\(=3^2-2\sqrt{9\times3}+\left(\sqrt{3}\right)^2\) 

\(=\left(3-\sqrt{3}\right)^2\) 

c) \(11+2\sqrt{30}\) 

\(=5+2\sqrt{5\times6}+6\) 

\(=\left(\sqrt{5}\right)^2+2\sqrt{5\times6}+\left(\sqrt{6}\right)^2\) 

\(=\left(\sqrt{5}+\sqrt{6}\right)^2\) 

d) \(14-2\sqrt{45}\)

\(=9-2\sqrt{9\times5}+5\)

\(=3^2-2\times3\times\sqrt{5}+\left(\sqrt{5}\right)^2\) 

\(=\left(3-\sqrt{5}\right)^2\)

10 tháng 7 2018

\(a.11+2\sqrt{30}=6+2.\sqrt{6}.\sqrt{5}+5=\left(\sqrt{6}+\sqrt{5}\right)^2\)

\(b.10+2\sqrt{21}=7+2\sqrt{7}.\sqrt{3}+3=\left(\sqrt{7}+\sqrt{3}\right)^2\)

\(c.6x-\sqrt{x}-1=6x+2\sqrt{x}-3\sqrt{x}-1=2\sqrt{x}\left(3\sqrt{x}+1\right)-\left(3\sqrt{x}+1\right)=\left(3\sqrt{x}+1\right)\left(2\sqrt{x}-1\right)\) \(d.14-2\sqrt{45}=14-6\sqrt{5}=9-2.3\sqrt{5}+5=\left(3-\sqrt{5}\right)^2\)

\(e.4x-3\sqrt{x}-1=4x-4\sqrt{x}+\sqrt{x}-1=4\sqrt{x}\left(\sqrt{x}-1\right)+\left(\sqrt{x}-1\right)=\left(\sqrt{x}-1\right)\left(4\sqrt{x}+1\right)\) \(j.12-2\sqrt{27}=9-2.3.\sqrt{3}+3=\left(3-\sqrt{3}\right)^2\)

10 tháng 7 2018

a) 4x-3√x-1=4x-4√x+√x-1=4√x(√x-1)+(√x+1)

=(4√x+1).(√x-1)

c) 12-2√27=9-2.3√3+3=32-2.3√3+(√3)2=(3-√3)2

d) 6x-√x-1=6x-3√x+2√x-1=3√x(2√x-1)+(2√x-1)

=(3√x+1).(2√x-1)

e) 11+2√30=6+2.√6.√5+5=(√6)2+2.√6.√5+(√5)2=(√6+√5)2

f) 10+2√21=7+2.√7.√3+3=(√7)2+2.√7.√3+(√3)2=(√7+√3)2

6 tháng 10 2021

tui lại 

NM
6 tháng 10 2021

úi sao bạn cũng là quản lý giống mình à, mình trả lời câu hỏi của bạn có được không nhỉ 

undefined

6 tháng 8 2020

mình không biết bạn ơi

6 tháng 8 2020

a. \(11+2\sqrt{10}=\left(\sqrt{10}+1\right)^2\)

b. \(12-2\sqrt{11}=\left(\sqrt{11}-1\right)^2\)

c.\(23+2\sqrt{22}=\left(\sqrt{22}+1\right)^2\)

14 tháng 6 2019

\(x\sqrt{x}+4x-12\sqrt{x}-27\)

\(=\left(x\sqrt{x}-27\right)+\left(4x-12\sqrt{x}\right)\)

\(=\left(\sqrt{x}-3\right)\left(x+3\sqrt{x}+9\right)+4\sqrt{x}\left(\sqrt{x}-3\right)\)

\(=\left(\sqrt{x}-3\right)\left(x+3\sqrt{x}+9+4\sqrt{x}\right)\)

\(=\left(\sqrt{x}-3\right)\left(x+7\sqrt{x}+9\right)\)

14 tháng 6 2019

a, \(\sqrt{a^2-b^2}-\sqrt{a^3+b^3}\)

\(=\sqrt{\left(a+b\right)\left(a-b\right)}-\sqrt{\left(a+b\right)\left(a^2-ab+b^2\right)}\)

\(=\sqrt{a+b}\left(\sqrt{a-b}-\sqrt{a^2-ab+b^2}\right)\)

27 tháng 8 2020

Bài 3:

a) Ta có: \(4+2\sqrt{3}\)

\(=3+2\cdot\sqrt{3}\cdot1+1\)

\(=\left(\sqrt{3}+1\right)^2\)

b) Ta có: \(7+4\sqrt{3}\)

\(=4+2\cdot2\cdot\sqrt{3}+3\)

\(=\left(2+\sqrt{3}\right)^2\)

c) Ta có: \(9+4\sqrt{5}\)

\(=5+2\cdot\sqrt{5}\cdot2+4\)

\(=\left(\sqrt{5}+2\right)^2\)

d) Ta có: \(31+10\sqrt{6}\)

\(=25+2\cdot5\cdot\sqrt{6}+6\)

\(=\left(5+\sqrt{6}\right)^2\)

e) Ta có: \(13+4\sqrt{3}\)

\(=12+2\cdot2\sqrt{3}\cdot1+1\)

\(=\left(2\sqrt{3}+1\right)^2\)

g) Ta có: \(21+12\sqrt{3}\)

\(=12+2\cdot2\sqrt{3}\cdot3+9\)

\(=\left(2\sqrt{3}+3\right)^2\)

h) Ta có: \(29+12\sqrt{5}\)

\(=20+2\cdot2\sqrt{5}\cdot3+3\)

\(=\left(2\sqrt{5}+3\right)^2\)

i) Ta có: \(49+8\sqrt{3}\)

\(=48+2\cdot4\sqrt{3}\cdot1\)

\(=\left(4\sqrt{3}+1\right)^2\)

k) Sửa đề: \(14-6\sqrt{5}\)

Ta có: \(14-6\sqrt{5}\)

\(=9-2\cdot3\cdot\sqrt{5}+5\)

\(=\left(3-\sqrt{5}\right)^2\)

l) Ta có: \(23-8\sqrt{7}\)

\(=16-2\cdot4\cdot\sqrt{7}+7\)

\(=\left(4-\sqrt{7}\right)^2\)

m) Ta có: \(15-4\sqrt{11}\)

\(=11-2\cdot\sqrt{11}\cdot2+4\)

\(=\left(\sqrt{11}-2\right)^2\)

n) Sửa đề: \(28-10\sqrt{3}\)

Ta có: \(28-10\sqrt{3}\)

\(=25-2\cdot5\cdot\sqrt{3}+3\)

\(=\left(5-\sqrt{3}\right)^2\)

o) Ta có: \(17-12\sqrt{2}\)

\(=9-2\cdot3\cdot2\sqrt{2}+8\)

\(=\left(3-2\sqrt{2}\right)^2\)

p) Ta có: \(43-30\sqrt{2}\)

\(=25-2\cdot5\cdot3\sqrt{2}+18\)

\(=\left(5-3\sqrt{2}\right)^2\)

q) Ta có: \(51-10\sqrt{2}\)

\(=50-2\cdot5\sqrt{2}\cdot1\)

\(=\left(5\sqrt{2}-1\right)^2\)

r) Ta có: \(49-12\sqrt{5}\)

\(=45-2\cdot3\sqrt{5}\cdot2+4\)

\(=\left(3\sqrt{5}-2\right)^2\)

20 tháng 6 2021

a) 2a−4b=2(a−2b)2a−4b=2(a−2b)

c) 2ax−2ay+2a=2a(x−y+1)2ax−2ay+2a=2a(x−y+1)

e) 3xy(x−4)−9x(4−x)=3x(x−4)(y+3)3xy(x−4)−9x(4−x)=3x(x−4)(y+3)

b,d xem lại đề

20 tháng 6 2021

không hiểu

 what are you doing?

20 tháng 8 2020

a) \(21-8\sqrt{5}=16-2\times4\times\sqrt{5}+5=\left(4-\sqrt{5}\right)^2\)

b) \(47-12\sqrt{11}=36-2\times6\times\sqrt{11}+11=\left(6-\sqrt{11}\right)^2\)

c) \(13-4\sqrt{3}=12-2\times1\times\sqrt{3}+1=\left(2\sqrt{3}-1\right)^2\)

d) \(43+30\sqrt{2}=25+2\times5\times3\sqrt{2}+18=\left(5+3\sqrt{2}\right)^2\)

e) \(41+24\sqrt{2}=9+2\times3\times4\sqrt{2}+32=\left(3+4\sqrt{2}\right)^2\)

g) \(29-12\sqrt{5}=9+2\times3\times2\sqrt{5}+20=\left(3+2\sqrt{5}\right)^2\)

h) \(49-8\sqrt{3}=48-2\times4\sqrt{3}\times1+1=\left(4\sqrt{3}-1\right)^2\)

i) \(37-12\sqrt{7}=28-2\times3\times2\sqrt{7}+9=\left(2\sqrt{7}-3\right)^2\)