\(187-\left\{\left[497-\left(8x+11\right):x\right]:3-78\right\}=150\)

\(\left[497-\left(8x+11\right):x\right]:3-78=37\)

\(\left[497-\left(8x+11\right):x\right]:3=115\)

\(497-\left(8x+11\right):x=345\)

\(8+\frac{11}{x}=152\)

\(\frac{11}{x}=144\)

\(x=\frac{11}{144}\)

1. \(\left(\frac{2}{11.13}+\frac{2}{13.15}+\frac{2}{15.17}+\frac{2}{17.19}+\frac{2}{19.21}\right)\times462-x=19\)

\(\left(\frac{13-11}{11.13}+\frac{15-13}{13.15}+\frac{17-15}{15.17}+\frac{19-17}{17.19}+\frac{21-19}{19.21}\right)\times462-x=19\)

\(\left(\frac{1}{11}-\frac{1}{13}+\frac{1}{13}-\frac{1}{15}+\frac{1}{15}-\frac{1}{17}+\frac{1}{17}-\frac{1}{19}+\frac{1}{19}-\frac{1}{21}\right)\times462-x=19\)

\(\left(\frac{1}{11}-\frac{1}{21}\right)\times462-x=19\)

\(\frac{10}{231}\times462-x=19\)

\(20-x=19\)

\(x=20-19\)

\(x=1\)

2.b \(187-[[497-(8\times x+11)\div x]\div3-78]=150\)

​​\(187-[[497-(\frac{8\times x}{x}+\frac{11}{x})]:3-78]=150\)

\(187-[(497-8-\frac{11}{x}):3-78]=150\)

\(187-[(489-\frac{11}{x}):3-78]=150\)

\(187-[\frac{489}{3}-\frac{33}{x}-78]=150\)

\(187-[163-\frac{33}{x}-78]=150\)

\(187-85+\frac{33}{x}=150\)

\(102+\frac{33}{x}=150\)

\(\frac{33}{x}=150-102\)

\(\frac{33}{x}=48\)

\(x=\frac{48}{33}=\frac{16}{11}\)

a) 2 x 12 x 43 + 3 x 32 x 8 + 25 x 6 x4

=(2 x12) x43+(3 x8) x32+(6 x4) x25

=24 x43+24 x32+ 24 x25

=24 x(43+32+25)

=24 x100

=2400

b) 78 x 31 + 78 x 24 + 17 x 78 + 28 x 78

=78x(31+24+17+28)

=78x100

=7800

thanks bạn nha

`@` `\text {Ans}`

`\downarrow`

`a,`

`93,57 \times 19,45 - 93,57 \times 9,45`

`= 93,57 \times (19,45 - 9,45)`

`= 93,57 \times 10`

`= 935,7`

`b,`

`815,5 \times 0,08 + 815,5 \times 0,02`

`= 815,5 \times (0,08 + 0,02)`

`= 815,5 \times 0,1`

`= 81,55`

`c,`

`11 \times 46,79 - 46,79`

`= 46,79 \times (11 - 1)`

`= 46,79 \times 10`

`= 467,9`

`d,`

`92,305 \times 108 - 92,305 \times 8`

`= 92,305 \times (108 - 8)`

`= 92,305 \times 100`

`= 9230,5`

`e,`

`189,28 \times 78 - 189,28 \times 68`

`= 189,28 \times (78 - 68)`

`= 189,28 \times 10`

`= 1892,8`

a) \(93,57\times19,45-93,57\times9,45\)

\(=93,57\times\left(19,45-9,45\right)\)

\(=93,57\times10\)

\(=935,7\)

b) \(815,5\times0,08+815,5\times0,02\)

\(=815,5\times\left(0,08+0,02\right)\)

\(=815,5\times0,1\)

\(=81,55\)

c) \(11\times46,72-46,79\)

\(=46,79\times\left(11-1\right)\)

\(=46,79\times10\)

\(=467,9\)

d) \(92,305\times108-92,305\times8\)

\(=92,305\times\left(108-8\right)\)

\(=92,305\times100\)

\(=9230,5\)

e) \(189,28\times78-189,28\times68\)

\(=189,28\times\left(78-68\right)\)

\(=189,28\times10\)

\(=1892,8\)

52 x (y :78 ) = 3380

( y : 78 ) = 3380 : 52

( y :78 ) = 65

y = 65 x 78

y = 5070

1/5x8 + 1/8x11 + 1/11x14 + ... + 1/xx(x+3) = 101/1540

1/3 x (3/5x8 + 3/8x11 + 3/11x14 + ... + 3/xx(x+3) = 101/1540

1/3 x (1/5 - 1/8 + 1/8 - 1/11 + 1/11 - 1/14 + ... + 1/x - 1/x+3) = 101/1540

1/3 x (1/5 - 1/x+3) = 101/1540

1/5 - 1/x+3 = 101/1540 : 1/3

1/5 - 1/x+3 = 303/1540

1/x+3 = 1/5 - 303/1540

1/x+3 = 1/308

=> x+3=308

=> x=308-3=305

vậy x=305

1/5x8 + 1/8x11 + 1/11x14 + ... + 1/xx(x+3) = 101/1540

1/3 x (3/5x8 + 3/8x11 + 3/11x14 + ... + 3/xx(x+3) = 101/1540

1/3 x (1/5 - 1/8 + 1/8 - 1/11 + 1/11 - 1/14 + ... + 1/x - 1/x+3) = 101/1540

1/3 x (1/5 - 1/x+3) = 101/1540

1/5 - 1/x+3 = 101/1540 : 1/3

1/5 - 1/x+3 = 303/1540

1/x+3 = 1/5 - 303/1540

1/x+3 = 1/308

=> x+3=308

=> x=308-3=305

vậy x=305

\(\Rightarrow x=\left(\frac{33}{5}.\frac{1}{6}-\frac{1}{8}.8+\frac{2}{15}.\frac{3}{100}\right).\frac{11}{4}\)

\(=\left(\frac{11}{10}-1+\frac{1}{250}\right).\frac{11}{4}=\frac{13}{125}.\frac{11}{4}=\frac{143}{500}\)

(11/1×12 + 11/12×23 + 11/23×34 + ... + 11/89×100) + x = 2/3

(1 - 1/12 + 1/12 - 1/23 + 1/23 - 1/34 + ... + 1/89 - 1/100) + x = 2/3

(1 - 1/100) + x = 2/3

99/100 + x = 2/3

x = 2/3 - 99/100

x = 200/300 - 297/300

x = -97/300

Vậy x =-97/300

^_^ ^_^ ☆☆☆