tính a)$\sqrt{25} \sqrt{9}-\sqrt{16}$ b)$\sqrt{0,16} \sqrt{0,01} \sqrt{0,25}$ c)$\left(\sqrt{3^2}\right)-\left(\sqrt{2^2}\right) \left(\sqrt{5^2}\right)$ d)\(\sqrt{4}-\left(-\sqrt{3}\right)^2...

1

LT

Lê Thanh Nhàn

3 tháng 9 2019

a) $\sqrt{25}+\sqrt{9}-\sqrt{16}$ = $\sqrt{5^2}+\sqrt{3^2}-\sqrt{4^2}$ = 5 + 3 - 4 = 4

b) $\sqrt{0,16}+\sqrt{0,01}+\sqrt{0,25}$ = 0,4 + 0,1 + 0,5 = 1

c) $\left(\sqrt{3^2}\right)-\left(\sqrt{2^2}\right)+\left(\sqrt{5^2}\right)$

= 3 - 2 + 5 = 6

d) $\sqrt{4}-\left(-\sqrt{3}\right)^2+\sqrt{49}$ = 2 - 3 + 7 = 6

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

= $\left(\sqrt{8}\right)^2-\left(\sqrt{27}\right)^2$ = 8 - 27 = -19

f) $\left(-2\sqrt{2}\right)^2+\left(3\sqrt{3}\right)^2$ = 8 + 27 = 35

HG

hương giang

3 tháng 9 2019

cảm ơn nhé

a) $\sqrt{9}+\sqrt{4}$ b) $\sqrt{0,25}-\sqrt{0,01}$ c) $\sqrt{\frac{16}{25}}-\sqrt{\frac{1}{81}}$ d) $2-\sqrt{0,36}$2. a) $\sqrt{64}-\sqrt{16}+\sqrt{\left(-3^2\right)}$ b) $\sqrt{121}+\sqrt{\left(-5\right)^2}-\sqrt{9}$c) $\sqrt{\frac{9}{4}}-\sqrt{\frac{16}{36}}-\sqrt{49}$ ...

A

Aoidễthương

17 tháng 7 2019

#Toán lớp 7

2

TM

tam mai

17 tháng 7 2019

1. a) 3+2=5

b) 0,5-0,1=0,4

c) 4/5-1/9=31/45

d) 2-0,6=1,4

2. a) 8-4+3=7

b) 11+5-3=13

c) 3/2-4/6-7-37/6

d) 4+5-6=3

A

Aoidễthương

17 tháng 7 2019

Mơn nhìu <3

P

phamthiminhanh

8 tháng 6 2021

...

Tính:$A=\sqrt{27}-2\sqrt{48}+3\sqrt{75}$$B=\sqrt{\left(\sqrt{5}-2\right)^2}-\sqrt{\left(\sqrt{5}-3\right)^2}$$C=\sqrt{\left(2\sqrt{3}+1\right)^2}+\sqrt{\left(2\sqrt{3}-5\right)^2}$$D=\sqrt{9-4\sqrt{5}}-\sqrt{14+6\sqrt{5}}$$E=\dfrac{4}{\sqrt{5}-2}-\dfrac{32}{\sqrt{5}+1}$$M=\dfrac{10}{3\sqrt{2}-4}+\dfrac{28}{3\sqrt{2}+2}$ please help...

1

MY

missing you =

8 tháng 6 2021

a,$\left(\sqrt{1\dfrac{9}{16}}-\sqrt{\dfrac{9}{16}}\right):5=\left(\sqrt{\dfrac{25}{16}}-\dfrac{3}{4}\right):5=\left(\dfrac{5}{4}-\dfrac{3}{4}\right):5$

$=\dfrac{1}{2}:5=\dfrac{1}{10}$

b,$\left(\sqrt{3}-2\right)^2\left(\sqrt{3}+2\right)^2=\left[\left(\sqrt{3}-2\right)\left(\sqrt{3}+2\right)\right]^2$

$=\left[3-4\right]^2=1$

c,$\left(11-4\sqrt{3}\right)\left(11+4\sqrt{3}\right)=11^2-\left(4\sqrt{3}\right)^2$

$=121-48=73$

d,$\left(\sqrt{2}-1\right)^2-\dfrac{3}{2}\sqrt{\left(-2\right)^2}+\dfrac{4\sqrt{2}}{5}+\sqrt{1\dfrac{11}{25}}.\sqrt{2}$

$=2-2\sqrt{2}+1-3+\dfrac{4\sqrt{2}}{5}+\sqrt{\dfrac{36}{25}.2}$

$=-2\sqrt{2}+\dfrac{4\sqrt{2}+6\sqrt{2}}{5}$

$=-2\sqrt{2}+\dfrac{10\sqrt{2}}{5}=-2\sqrt{2}+2\sqrt{2}=0$

e,$\left(1+\sqrt{2021}\right)\sqrt{2022-2\sqrt{2021}}$

$=\left(1+\sqrt{2021}\right)\sqrt{2021-2\sqrt{2021}.1+1}$

$=\left(1+\sqrt{2021}\right)\sqrt{\left(\sqrt{2021}-1\right)^2}$

$=\left(1+\sqrt{2021}\right)\left(\sqrt{2021}-1\right)$

$=\sqrt{2021}-1+\sqrt{2021^2}-\sqrt{2021}=2020$

Đúng(1)

BP

Bùi Phúc Hoàng Linh

14 tháng 10 2020

Giúp mik với

Tính

a)$\frac{2}{3}\sqrt{81}-\left(\frac{-3}{4}\right).\sqrt{\frac{9}{64}}+\left(\frac{\sqrt{2}}{3}\right)^2$

b)$\left(-\sqrt{\frac{5}{4}}\right)^2-\sqrt{\frac{9}{4}}:\left(-4,5\right)-\sqrt{\frac{25}{16}}.\sqrt{\frac{64}{9}}$

c)$-2^4-\left(-2\right)^2:\left(-\sqrt{\frac{16}{121}}\right)-\left(-\sqrt{\frac{2}{3}}\right)^2:\left(-2\frac{2}{3}\right)$

#Toán lớp 7

0

AQ

Anh Quynh

4 tháng 8 2021

0

QE

Quynh Existn't

26 tháng 6 2021

...

2

NN

Nguyễn Ngọc Lộc

26 tháng 6 2021

$A=2.\left|\left(-3\right)\right|^3+2.\left(-2\right)^2-4\left|\left(-2\right)^3\right|$

$=54+8-32=30$

$B=\left|\sqrt{2}-2\right|+\left|\sqrt{2}-3\right|=2-\sqrt{2}+3-\sqrt{2}$

$=5-2\sqrt{2}$

$C=\left|3-\sqrt{3}\right|-\left|1+\sqrt{3}\right|=3-\sqrt{3}-1-\sqrt{3}$

$=2-2\sqrt{3}$

$D=\left|5+\sqrt{6}\right|-\left|\sqrt{6}-5\right|=5+\sqrt{6}-5+\sqrt{6}$

$=2\sqrt{6}$

$E=\sqrt{15^2}-\sqrt{5^2}=15-5=10$

Đúng(2)

Y

Yeutoanhoc

26 tháng 6 2021

`A=2sqrt{(-3)^6}+2sqrt{(-2)^4}-4sqrt{(-2)^6}=2|(-3)^3|+2|(-2)^2|-4|(-2)^3|=54+8-32=30` $\\$ `B=sqrt{(sqrt2-2)^2}+sqrt{(sqrt2-3)^2}=2-sqrt2+3-sqrt2=5-2sqrt2` $\\$ `C=sqrt{(3-sqrt3)^2}-sqrt{(1+sqrt3)^2}=3-sqrt3-sqrt3-1=2-2sqrt3` $\\$ `D=sqrt{(5+sqrt6)^2}-sqrt{(sqrt6-sqrt5)^2}=5+sqrt6-5+sqrt6=2sqrt6` $\\$ `E=sqrt{17^2-8^2}-sqrt{3^2+4^2}=sqrt{289-64}-sqrt{9+16}=sqrt(225)-sqrt{25}=15-5=10`

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M

manh

30 tháng 9 2023

a : $\sqrt{2-\sqrt{3}}+\sqrt{2+\sqrt{3}}$

b : $\sqrt{4-\sqrt{7}}-\sqrt{4+\sqrt{7}}$

c : $\sqrt{\left(2\sqrt{5}+1\right)^2}-\sqrt{\left(\sqrt{5}-2\right)^2}$

d : $\sqrt{52-16\sqrt{3}}+\sqrt{\left(4\sqrt{3}-7\right)^2}$

3

AH

Akai Haruma

Giáo viên

30 tháng 9 2023

a.

$A=\sqrt{2-\sqrt{3}}+\sqrt{2+\sqrt{3}}$

$A\sqrt{2}=\sqrt{4-2\sqrt{3}}+\sqrt{4+2\sqrt{3}}$

$A\sqrt{2}=\sqrt{(\sqrt{3}-1)^2}+\sqrt{(\sqrt{3}+1)^2}$

$=|\sqrt{3}-1|+|\sqrt{3}+1|=\sqrt{3}-1+\sqrt{3}+1=2\sqrt{3}$

$\Rightarrow A=2\sqrt{3}: \sqrt{2}=\sqrt{6}$

---------------------

$B=\sqrt{4-\sqrt{7}}-\sqrt{4+\sqrt{7}}$

$B\sqrt{2}=\sqrt{8-2\sqrt{7}}-\sqrt{8+2\sqrt{7}}$

$B\sqrt{2}=\sqrt{(\sqrt{7}-1)^2}-\sqrt{(\sqrt{7}+1)^2}$

$=|\sqrt{7}-1|-|\sqrt{7}+1|=\sqrt{7}-1-(\sqrt{7}+1)=-2$

$\Rightarrow B=-2:\sqrt{2}=-\sqrt{2}$

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H

⭐Hannie⭐

30 tháng 9 2023

$a,\sqrt{2-\sqrt{3}}+\sqrt{2+\sqrt{3}}$

$A-\sqrt{2}=\left(\sqrt{2-\sqrt{3}}-\sqrt{2+\sqrt{3}}\right)\cdot\sqrt{2}\\ =\sqrt{2-\sqrt{3}}\cdot\sqrt{2}-\sqrt{2+\sqrt{3}}\cdot\sqrt{2}\\ =\sqrt{\left(2-\sqrt{3}\right)\cdot2}-\sqrt{\left(2+\sqrt{3}\right)\cdot2}\\ =\sqrt{4-2\sqrt{3}}-\sqrt{4+2\sqrt{3}}\\ =\sqrt{3-2\sqrt{3}+1}-\sqrt{3+2\sqrt{3}+1}\\ =\sqrt{\left(\sqrt{3}-1\right)^2}-\sqrt{\left(\sqrt{3}+1\right)^2}\\ =\left|\sqrt{3}-1\right|-\left|\sqrt{3}+1\right|\\ =\sqrt{3}-1-\sqrt{3}-1\\ =-2$

Ta có :

$A-\sqrt{2}=-2\\ \Leftrightarrow A=\dfrac{-2}{\sqrt{2}}=\dfrac{-\left(\sqrt{2}\right)^2}{\sqrt{2}}=-\sqrt{2}$

__

C làm giống câu a, nhé.

__

$\sqrt{\left(2\sqrt{5}+1\right)^2}-\sqrt{\left(\sqrt{5}-2\right)^2}\\ =\left|2\sqrt{5}+1\right|-\left|\sqrt{5}-2\right|\\ =2\sqrt{5}+1-\sqrt{5}+2\\ =3+\sqrt{5}$

__

$\sqrt{52-16\sqrt{3}}+\sqrt{\left(4\sqrt{3}-7\right)^2}\\ =\sqrt{48-2\cdot4\cdot\sqrt{3}\cdot2+4}+\left|4\sqrt{3}-7\right|\\ =\sqrt{\left(4\sqrt{3}\right)^2-2\cdot4\cdot\sqrt{3}\cdot2+2^2}+4\sqrt{3}-7\\ =\sqrt{\left(4\sqrt{3}-2\right)^2}+4\sqrt{3}-7\\ =4\sqrt{3}-2+4\sqrt{3}-7\\ =8\sqrt{3}-9$

KA

Khánh An Ngô

31 tháng 5 2023

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