b,(723+277).2001-(456+544).1010-389-611

=1000.2001-1000.1010-(389+611)

=1000.2001-1000.1010-1000

=1000.(2001-1010-1)

=1000.990

=990000

a, 9².53+12.9²-81+36.9²

=9².(53+12+36)-81

=81.101-81

=8181-81

=8100

đáp án là:2004456

2005 x 456 + 2004 x 544 = 2004456

theo bai co 1/3+1/6+...+2/x.x+1=499/1000

(=)2/2.3+2/3.4+...+2/x.(x+1)=499/1000

(=)2(1/2-...-1/x+1)=499/1000

(=)1/2-1/x+1=499/2000

(=)1/x+1=501/2000

den day thi minh chiu roi!

\(x+x+x+x+x+x+x+x+999=456+572\)

\(\Rightarrow1x+1x+1x+1x+1x+1x+1x+1x+999=1028\)

\(\Rightarrow\left(1+1+1+1+1+1+1+1\right)x=1028-999\)

\(\Rightarrow8x=27\Rightarrow x=27\div8=\frac{27}{8}\)

x + x + x + x + x +x + x + x + 999 = 456 + 572

<=>(1 + 1 + 1 + 1 + 1+ 1 + 1 + 1).x + 999 = 1028

<=>8x + 999 = 1028

<=>8x = 1028 - 999

<=>8x = 29

<=>x=3.625

Thử lại

3,625 + 3,625 + 3,625 + 3,625 + 3,625 + 3,625 + 3,625 + 3,625 + 999 = 456 + 572

1028 = 1028

a)   \(-x+821+534=499+\left(x-84\right)\)

\(-x-x=499-84-821-534\)

\(-2x=-940\)

\(x=470\)

b)  \(x-96=\left(448-x\right)-150\)

\(x+x=448-150+96\)

\(2x=394\)

\(x=197\)

c)  \(-\left(754+x\right)=\left(x-12-741\right)-23\)

\(-754-x=x-12-741-23\)

\(-x+x=-12-741-23+754\)

\(0x=2\)

\(x\)ko tồn tại

d) \(\left(6+x\right)-\left(17-21\right)=-25\)

\(6+x-17+21=-25\)

\(x=-25-6+17-21\)

\(x=-35\)

e)  \(17-\left(x+2\right)=3\)

\(17-x-2=3\)

\(-x=3-17+2\)

\(-x=-12\)

\(x=12\)

h)  \(-10-\left(31-x\right)=40\)

\(-10-31+x=40\)

\(x=40+10+31\)

\(x=81\)

k mk nha bạn    

a) - x + 821 + 534 = 499 + ( x - 84 )

<=> -x + 821 + 534 = 499 + x - 84

<=> 2x = 940

<=> x = 470

b, x - 96 = ( 448 - x ) - 150

<=> x - 96 = 448 - x - 150

<=> 2x = 394

<=> x = 157

Cac phan con lai tuong tu

Tìm x

a) (x+3)/200 + (x+4)/199 + (x+5)/198= -3

b) (x+4)/2000+ (x+6)/999+(x+8)/499+7=0

c) |x-4| - |2x-1|=6

a) \(-x+821+534=499+\left(x-84\right)\)

\(\Leftrightarrow-x+821+534=499+x-84\)

\(\Leftrightarrow821+534-499+84=x+x\)

\(\Leftrightarrow940=2x\)

\(\Leftrightarrow x=\dfrac{940}{2}\)

\(\Leftrightarrow x=470\)

Vậy \(x=470\)

b) \(x-96=\left(448-x\right)-150\)

\(\Leftrightarrow x-96=448-x-150\)

\(\Leftrightarrow x+x=96+448-150\)

\(\Leftrightarrow2x=394\)

\(\Leftrightarrow x=\dfrac{394}{2}\)

\(\Leftrightarrow x=197\)

Vậy \(x=197\)

c) \(- (754 + x) = (x - 12 - 741) - 23\)

\(\Leftrightarrow-754-x=x-12-741-23\)

\(\Leftrightarrow-754+12+741+23=x+x\)

\(\Leftrightarrow22=2x\)

\(\Leftrightarrow x=\dfrac{22}{2}\)

\(\Leftrightarrow x=11\)

Vậy \(x=11\)

d) \((6 + x) - (17 - 21) = -25\)

\(\Leftrightarrow6+x-17+21=-25\)

\(\Leftrightarrow x=-25-6+17-21\)

\(\Leftrightarrow x=-35\)

Vậy \(x=-35\)

e) \(17-\left(x+2\right)=3\)

\(\Leftrightarrow17-x-2=3\)

\(\Leftrightarrow17-2-3=x\)

\(\Leftrightarrow x=12\)

Vậy \(x=12\)

h) \(-10 - (31 - x) = 40\)

\(\Leftrightarrow-10-31+x=40\)

\(\Leftrightarrow x=40+10+31\)

\(\Leftrightarrow x=81\)

Vậy \(x=81\)

a) - x + 821 + 534 = 499 + (x - 84)

= (856 - x) + 499 = 499 + ( x- 84)

=> (x-84) = (856 - x).

= ...

nhanh đi mình cần gấp 

giúp mình với

kho qua khong giai duoc