` B = (1 - 1/4) × ( 1 - 1/9) × (1 - 1/25) × 1\(\dfrac{ }{ }\) (3/5)`

` B = 3/4 × 8/9 × 24/25 × 8/5`

` B = (3/4 × 8/9) × (24/25 × 8/5)`

`B = 2/3 × 1 ,536`

`B = 1,024`

`20 + (4^2 - 4) - 2`

`= 20 + (16 - 4) - 2`

`= 20 + 16 - 4 - 2`

`= (20 - 2) + (16 - 4)`

`= 18 + 12`

`= 30`

`123 + 123 = 246`(C1)

`123 + 123 = 123 × 2 = 246`(C2)

\(\left(\dfrac{1}{1.2}+\dfrac{1}{2.3}+\dfrac{1}{3.4}+\dfrac{1}{4.5}\right).x=16\)

\(\left(1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{5}\right).x=16\)

\(\left(1-\dfrac{1}{5}\right).x=16\)

\(\dfrac{4}{5}.x=16\)

     \(x=16:\dfrac{4}{5}\)

    \(x=16.\dfrac{5}{4}\)

    \(x=4.5\)

   \(x=20\)

\(x-\dfrac{5}{4}-\dfrac{7}{5}=\dfrac{9}{20}\)

\(x-\dfrac{5}{4}\)        \(=\dfrac{9}{20}+\dfrac{7}{5}\)

\(x-\dfrac{5}{4}\)        \(=\dfrac{37}{20}\)

\(x\)                \(=\dfrac{37}{20}+\dfrac{5}{4}\)

\(x\)                \(=\dfrac{37}{20}+\dfrac{25}{20}\)

\(x\)                \(=\dfrac{31}{10}\)

Vậy \(x=\dfrac{31}{10}\)

Vì tài khoản của cậu không phải là VIP nhé!

`816 + 1265 + 2184 + 735`

`= (816 + 2184) + (1265 + 735)`

`= 3000 + 2000`

`= 5000`

C.5000

`9/19 - 1,251 + 1,251 + 10/19`

`= (9/19 + 10/19) + (1,251 - 1,251)`

`= 1 + 0`

`= 1`

`(-8) × 24,7 × 0,125`

`= [(-8) × 0,125] × 24,7`

`= (-1) × 24,7`

`= (-24,7)`

`0,25 × 7/15 - 1/4 × (-8/15) + 0,25 `

`= 0,25 × 7/15 - 0,25 × (-8/15) + 0,25 × 1`

`= 0,25 × [7/15 -(-8/15) + 1]`

`= 0,25 × [7/15 + 8/15 + 1]`

`= 0,25 × 2`

`= 0,5`

`59 + 3(x - 8) = 53`

`         3(x - 8)  = 53 - 59`

`         3(x - 8) = -6`

`             x - 8  = -6 ÷ 3`

`             x - 8 = -2`

`             x       = -2 + 8`

`            x        = 6`

Vậy `x = 6`

Ps . Chj nhìn lộn,sorry

`59 + 3(x - 8) = 53`

`         3(x - 8)  = 53 - 59`

`         3(x - 8) = -6`

`             x - 8  = -6 ÷ 3`

`             x - 8 = -2`

`             x       = -2 + 8`

`            x        = 6`

Vậy `x = 6`

Ps . Chj nhìn lộn,sorry