Ta có

\(27-\left[20-\left(36-30^2\right)\right]=27-\left(20-6^2\right)=27-\left(20-36\right)\)

\(27-\left(-16\right)=27+16=43\)

b)\(119+\left(-213\right)+212+\left(-118\right)+2012=\left[119+\left(-118\right)\right]+\left[213+\left(-212\right)\right]+2012\)\(1+\left(-1\right)+2012=2012\)

Tick nha nguyen hoang le thi

a)43

b)2012

các bạn cho mình vài cái li-ke cho tròn 405 với 

27-[20-(36-30) mu 2]

=27-[20-6 mu 2]

=27-[20-36]

=27-(-16)

=43

b)119+(-213)+212+(-118)+2012

=(-213)+(-118)+119+212+2012

=(-331)+119+212+2012

=(-212)+212+2012

=0+2012

=2012

ai tích mình ,mình sẽ tích lại người đó ,chắc chắn đó ,minh tinh nhanh đó nha 

thanks

119+(-213)+212+(-118)+2012=(-94)+212+(-118)+2012=118+(-118)+2012=0+2012=2012

1/ M= [119+(-118)] + [(-213)+212)] + 2009

M= 1                 +        -1         + 2009

M= 2009

2/ N = (223- 23) + (132 - 32) + (187-27)

   N= 200 + 100 + 160 

   N= 300 + 160

   N= 460

OLM duyệt đi

a/ A= 119+(-213)+212+(-118)+2009

A= ! - 1 + 2009

A= 2009

b/ B=223+132+187-23-32-87

B = 200 + 100 + 100

B = 400

c/ C= -2012+(-596)+(-201)+496+301

C = -2012 - 100 + 100

C = -2012

 d/ D= -329+(15-101)-(25-440)

D = 0

hok tốt!!!

\(a,A=119+\left(-213\right)+212+\left(-118\right)+2009\)

\(A=\left(119+212+2009\right)+\left[\left(-213\right)+\left(-118\right)\right]\)

\(A=2340+\left(-331\right)\)

\(A=2009\)

\(b,B=223+132+187-23-32-87\)

\(B=\left(223+132+187\right)+\left(-23-32-87\right)\)

\(B=542-142\)

\(B=400\)

b: \(=15\left(141+19\right)=15\cdot160=24000\)

c: \(=2^3\cdot\left(17-14\right)=8\cdot3=24\)

M = 119 - 213 + 212 - 118 + 2009

= ( 119 - 118 ) - ( 213 - 212 ) + 2009

= 1 - 1 + 2009

= 2009 

=(119-118)-(213-212=2009

=1-1+2009

=2009

a) Ta có: \(\dfrac{2\sqrt{8}-\sqrt{12}}{\sqrt{18}-\sqrt{48}}-\dfrac{\sqrt{5}+\sqrt{27}}{\sqrt{30}+\sqrt{162}}\)

\(=\dfrac{-2\left(\sqrt{3}-\sqrt{8}\right)}{\sqrt{6}\left(\sqrt{3}-\sqrt{6}\right)}-\dfrac{\sqrt{5}+\sqrt{27}}{\sqrt{6}\left(\sqrt{5}+\sqrt{27}\right)}\)

\(=\dfrac{-3}{\sqrt{6}}=\dfrac{-3\sqrt{6}}{6}=\dfrac{-\sqrt{6}}{2}\)

b) Ta có: \(\left(1+\sqrt{2}+\sqrt{3}\right)\left(1-\sqrt{2}-\sqrt{3}\right)\)

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

\(=1-5-2\sqrt{6}\)

\(=-4-2\sqrt{6}\)

Giải

Bài 1

\(1,a,-40-37-\left(-29\right)\\ =-40-37+29\\ =-77+29=-48\\ b,27+\left(-36\right)-\left(-45\right)=27-36+45\\ =-9+45\\ =36\\ c,-125-\left[\left(-18\right)-125\right]\\ =-125+18+125\\ =\left(-125+125\right)+18\\ =18\\ d,140+\left[\left(-184\right)-140\right]\\ =140-184-140\\ =\left(140-140\right)-184\\ =0-184\\ =-184\)

Bài 2 

\(a,x-\left(-15\right)=-8\\ =>x+15=-8\\ =>x=-8-15\\ =>x=-23\\ b,-40-x=-35\\ =>x=\left(-40\right)-\left(-35\right)\\ =>x=-40+35\\ =>x=-5\\ c,x+\left(-50\right)=-27\\ =>x-50=-27\\ =>x=-27+50\\ =>x=23\)

1, Thực hiện phép tính:

\(a,-40+\left(-37\right)-\left(-29\right)=-77-\left(-29\right)=-48\)

\(b,27+\left(-36\right)-\left(-45\right)=-9-\left(-45\right)=36\)

\(c,-125-\left[\left(-18\right)-125\right]=-125-\left(-143\right)=18\)

\(d,140+\left[\left(-184\right)-140\right]=140+\left(-324\right)=-184\)

2, Tìm x biết:

\(a,x-\left(-15\right)=-8\)

\(x=-8+\left(-15\right)\)

\(x=-23\)

\(b,-40-x=-35\)

\(x=-40-\left(-35\right)\)

\(x=-5\)

\(c,x+\left(-50\right)=-27\)

\(x=-27-\left(-50\right)\)

\(x=23\)

 Bài 1: