\(-\dfrac{4}{7}-x=\dfrac{3}{5}-2x\\ \Rightarrow-x+2x=\dfrac{3}{5}+\dfrac{4}{7}\\ \Rightarrow x=\dfrac{21}{35}+\dfrac{20}{35}\\ \Rightarrow x=\dfrac{41}{35}\)

Vậy `x=41/35`

__

\(\dfrac{3}{7}x-\dfrac{2}{3}x=\dfrac{10}{21}\\ \Rightarrow\left(\dfrac{3}{7}-\dfrac{2}{3}\right)x=\dfrac{10}{21}\\ \Rightarrow\left(\dfrac{9}{21}-\dfrac{14}{21}\right)x=\dfrac{10}{21}\\ \Rightarrow\dfrac{-5}{21}x=\dfrac{10}{21}\\ \Rightarrow x=\dfrac{10}{21}:\left(-\dfrac{5}{21}\right)\\ \Rightarrow x=-2\)

Vậy `x=-2`

a)

-4/7 - x = 3/5 - 2x

2x - x = 3/5 + 4/7

x = 41/35

Vậy x = 41/35

b)

3/7.x - 2/3.x = 10/21

x(3/7 - 2/3) = 10/21

x.(-5/21) = 10/21

x = 10/21 : (-5/21) = -2

Vậy x = -2

chỉ cần đáp án thôi nha

bằng 4 nhé

tính nhanh hả bn ?

hay là tính giá trị biểu thức

tính nhanh : (6/5 + 4/5) + (4/11+7/11)+(5/21+16/21)

=1/2 +1 +1

=5/2

Ta có:

6+1=7

7+2=9

9+3=12

12+4=16

................

Số thứ 2016 là

6+[(2015-1):1+1].(2015+1):2=2031126

Vậy số thứ 2016 là 2031126

Nhân hết ra rồi rút gọn thôi bạn:

\(A=\left(2^9+2^7+1\right)\left(2^{23}-2^{21}+2^{19}-2^{17}+2^{14}-2^{10}+2^9-2^7+1\right).\)

\(=2^{32}-2^{30}+2^{28}-2^{26}+2^{23}-2^{19}+2^{18}-2^{16}+2^9\)\(+2^{30}-2^{28}+2^{26}-2^{24}+2^{21}-2^{17}+2^{16}-2^{14}+2^7+2^{23}-2^{21}+2^{19}-2^{17}+2^{14}-2^{10}\)\(+2^9-2^7+1\)

\(=2^{32}+\left(2^{23}+2^{23}-2^{24}\right)+\left(2^{18}-2^{17}-2^{17}\right)+\left(2^9+2^9-2^{10}\right)+1=2^{32}+1\)

Thanks Witch Rose_ Phù thủy hoa hồng !

11×[(62+(-12)]+50+11

11×51+50+11

561+50+11

611+11

622

(5/13+8/13)+(-20/41+-21/41)+-5/7

1+-1+-5/7

-5/7

a)

11 x 62 + -12 x 11 + 50 + 11

= 11 x (62 + -12) + 50 + 11

= 11 x 50 + 50 + 11

= (11 + 11) x (50 + 50)

= 22 x 100

= 2200

b)

5/13 + -5/7 + -20/41 + 8/13 + -21/41

= (5/13 + 8/13) + (-20/41 + -21/41) + -5/7

= 1 + -1 + -5/7

= -5/7

\(\frac{21^4}{27\cdot(-343)}+7\)

\(=\frac{(3\cdot7)^4}{3^3\cdot(-7)^3}+7\)

\(=\frac{3^4\cdot7^4}{3^3\cdot(-7)^3}+7\)

\(=3\cdot(-7)+7=-14\)

kết quả bằng 23/420 nha

1/28 - 1/21 + 1/15 = 23/420

Tk mk nha

=-1/84+1/15

=23/420