Với những dạng toán này thì em phải tìm \(x\) dưới dạng tổng quát em nhé.

    2\(x\) - 5 \(⋮\) 17

⇔ (2\(x\) - 5)  \(\times\) 9 ⋮ 17

⇔ 18\(x\) - 45 ⋮ 17

⇔ 17\(x\) + \(x\) - 34 - 11 ⋮ 17

⇔ (17\(x\) - 34) + \(x\) - 11 ⋮ 17

⇔ 17.(\(x\) - 34) + \(x\) - 11 ⋮ 17

⇔                    \(x-11\) ⋮ 17

⇔ \(x\) = 17k + 11( k \(\in\) Z)

Vậy \(x\in\) A = {\(x\in\)Z/\(x\) = 17k + 11; k \(\in\)Z}

Chưa có đề bài ý em

(5⁷ + 5⁹).(6⁸ + 6¹⁰).(2⁴ - 4²)

= (5⁷ + 5⁹).(6⁸ + 6¹⁰).(16 -16)

= (5⁷ + 5⁹).(6⁸ + 6¹⁰).0

= 0 

`@` `\text {Ans}`

`\downarrow`

Thay `a = -1; b = 2`

`B = 9*(-1)*5*2*2`

`= -9 * 5 * 2^2`

`= -45 * 2^2`

`= -180`

Vậy, `B = -180.`

* là gì vậy

  (13\(\dfrac{3}{5}\) + 4\(\dfrac{3}{4}\)) - 8\(\dfrac{3}{5}\)

= 13\(\dfrac{3}{5}\) + 4\(\dfrac{3}{4}\)  - 8\(\dfrac{3}{5}\) 

= (13\(\dfrac{3}{5}\) - 8\(\dfrac{3}{5}\)) + 4\(\dfrac{3}{4}\)

=   5 +  4\(\dfrac{3}{4}\)

= \(\dfrac{39}{4}\)

(13 3/5 + 4 3/4) - 8 3/5

=13 3/5 + 4 3/4 - 8 3/5

=(13 3/5 - 8 3/5) + 4 3/4

=5+4 3/4

=39/4

(-12.\(\dfrac{2}{7}\) + \(\dfrac{8}{9}\): 3\(\dfrac{1}{2}\) - \(\dfrac{2}{7}\).\(\dfrac{5}{18}\)). 3\(\dfrac{1}{2}\)

(-\(\dfrac{24}{7}\) +  \(\dfrac{8}{9}\):\(\dfrac{7}{2}\) - \(\dfrac{5}{63}\)). \(\dfrac{7}{2}\)

= (-\(\dfrac{24}{7}\) + \(\dfrac{16}{63}\) - \(\dfrac{5}{63}\)).\(\dfrac{7}{2}\)

= (\(-\dfrac{216}{63}\) + \(\dfrac{16}{63}\) - \(\dfrac{5}{63}\)). \(\dfrac{7}{2}\)

=  - \(\dfrac{205}{63}\). \(\dfrac{7}{2}\)

= - \(\dfrac{205}{18}\) 

( \(\dfrac{1}{2}\) - \(\dfrac{13}{14}\)): \(\dfrac{5}{7}\) - (- \(\dfrac{2}{21}\) + \(\dfrac{1}{7}\)) : \(\dfrac{5}{7}\)

(\(\dfrac{7}{14}\) - \(\dfrac{13}{14}\)): \(\dfrac{5}{7}\) - ( - \(\dfrac{2}{21}\) + \(\dfrac{3}{21}\)): \(\dfrac{5}{7}\)

- \(\dfrac{6}{14}\): \(\dfrac{5}{7}\)  - \(\dfrac{1}{21}\): \(\dfrac{5}{7}\)

= - (\(\dfrac{3}{7}\) + \(\dfrac{1}{21}\)): \(\dfrac{5}{7}\)

= -\(\dfrac{10}{21}\): \(\dfrac{5}{7}\)

= - \(\dfrac{2}{3}\) 

\(\left(-\dfrac{3}{4}+\dfrac{5}{13}\right):\dfrac{2}{7}-\left(2\dfrac{1}{4}+\dfrac{8}{13}\right):\dfrac{2}{7}\\ =\left(-\dfrac{3}{4}+\dfrac{5}{13}\right)\times\dfrac{7}{2}-\left(\dfrac{9}{4}+\dfrac{8}{13}\right)\times\dfrac{7}{2}\\ =\left(-\dfrac{3}{4}+\dfrac{5}{13}-\dfrac{9}{4}+\dfrac{8}{13}\right)\times\dfrac{7}{2}\\ =\left[\left(-\dfrac{3}{4}-\dfrac{9}{4}\right)+\left(\dfrac{5}{13}+\dfrac{8}{13}\right)\right]\times\dfrac{7}{2}\\ =\left(-\dfrac{12}{4}+\dfrac{13}{13}\right)\times\dfrac{7}{2}\\ =\left(-3+1\right)\times\dfrac{7}{2}\\ =-2\times\dfrac{7}{2}\\ =-\dfrac{14}{2}\\ =-7\)

use your brain

\(\text{∘ Ans}\)

\(\downarrow\)

\(\left(-\dfrac{3}{4}+\dfrac{5}{13}\right)\div\dfrac{2}{7}-\left(2\dfrac{1}{4}+\dfrac{8}{13}\right)\div\dfrac{2}{7}\)

`=`\(\left(-\dfrac{3}{4}+\dfrac{5}{13}-2\dfrac{1}{4}+\dfrac{8}{13}\right)\div\dfrac{2}{7}\)

`=`\(\left[\left(-\dfrac{3}{4}-2\dfrac{1}{4}\right)+\left(\dfrac{5}{13}+\dfrac{8}{13}\right)\right]\div\dfrac{2}{7}\)

`=`\(\left[\left(-\dfrac{3}{4}-\dfrac{9}{4}\right)+\dfrac{13}{13}\right]\div\dfrac{2}{7}\)

`=`\(\left(-3+1\right)\div\dfrac{2}{7}\)

`=`\(\left(-2\right)\div\dfrac{2}{7}=-7\)

=(-3/4+5/13).7/2-(2 1/4+8/13).7/2

\(=\dfrac{7}{2}\cdot\left(-\dfrac{3}{4}+\dfrac{5}{13}-2\dfrac{1}{4}+\dfrac{8}{13}\right)\\ =\dfrac{7}{2}\cdot\left(-2\right)=-7\)

3/5:(-1/15-1/6)+3/5:(-1/3-11/5)

=5/3 x(-1/15-1/6)+5/3 x(-1/3-11/5)

=5/3(-1/15-1/6-1/3-11/5)

=5/3 x(-83/30)

=-83/18

  - \(\dfrac{5}{7}\) - (-\(\dfrac{5}{67}\)) + \(\dfrac{13}{10}\) + \(\dfrac{1}{2}\) + (- 1\(\dfrac{5}{6}\)) + 1\(\dfrac{3}{14}\) - (-\(\dfrac{2}{5}\))

= (- \(\dfrac{5}{7}\) + 1\(\dfrac{3}{14}\)+ \(\dfrac{1}{2}\))+ \(\dfrac{5}{67}\) - \(\dfrac{11}{6}\) + (\(\dfrac{13}{10}\)   + \(\dfrac{2}{5}\)) 

= (-\(\dfrac{10}{14}\) + \(\dfrac{17}{14}\)+ \(\dfrac{1}{2}\)) + \(\dfrac{5}{67}\) - \(\dfrac{11}{6}\) + (\(\dfrac{13}{10}\) + \(\dfrac{4}{10}\)) 

= (\(\dfrac{1}{2}\) + \(\dfrac{1}{2}\)) + \(\dfrac{5}{67}\)  - \(\dfrac{11}{6}\)+ \(\dfrac{17}{10}\)

=  1 + \(\dfrac{5}{67}\) - \(\dfrac{11}{6}\) + \(\dfrac{17}{10}\)

= \(\dfrac{2010}{2010}\) + \(\dfrac{150}{2010}\) - \(\dfrac{3685}{2010}\) + \(\dfrac{3417}{2010}\)

= \(\dfrac{1892}{2010}\)

= \(\dfrac{946}{1005}\)