A, 7[x + 5] - 20 = 190

7x + 35 - 20 = 190

7x + 15 = 190

7x = 175

x = 25

B, 155 - 10[x + 1] = 55

155 - 10x - 10 = 55

-10x + 90 = 55

-10x = -35

x = 3.5

C, 6[x + 2^3] + 40 = 100

6[x + 8] + 40 = 100

6x + 48 + 40 = 100

6x + 88 = 100

6x = 1

2 x = 2

D, 15x - 133 = 17

15x = 150

x = 10

E, 90[x + 2] = 45

90x + 180 = 45

90x = -135

x = -1.5

F, 4x + 54 = 82

4x = 28

x = 7

G, 17x - 20 = 14

17x = 34

x = 2

a, A = \(\frac{20^8+1}{20^9+1}\)

22 giờ 8 phút

=21 giờ 68 phút

=22 giờ 8 phút

= 22 giờ 8 phút

#\(N\)

`a, -677*54+54.(-125)+2.54`

`=54.(-677+-125+2)`

`=54.(-800)`

`=-43200`

`b, -(324-267+252)+(133-76)`

`=-324+267-252+133-76`

`= (-324+-76)+(133+267)-252`

`=-400+400-252`

`=-252`

a: =54(-677-125+2)

=54*(-800)

=-43200

b: =-324+267-252+133-76

=-400+400-252

=-252

a. -677 . 54 + 54 . ( - 125 ) + 2. 54

= 54 . ( -677 + ( -125 ) + 2 )

= 54 . ( -802 + 2 )

= 54 . ( -800 )

= -43200

b.- (324 - 267 + 252) + (133 - 76)

= 324 - 267 + 252 + 133 -76

= 324 +76 - 267 + 133 -252

= 400 - 400 +252

= -252

54 x 133 x 45 x 133 + 133

= ( 54 + 45 + 1 ) x    133

=      100            x    133

=             13300

54 x 133 + 45 x 133 + 133

= 133 x ( 45 + 54 + 1 )

= 133 x 100

= 13300

54 x 133 + 45 x 133 + 133

= ( 54 + 45 + 1 ) x 133

= 100 x 133

= 13300

`x-14 +x+54+x+20=300`

`=> (x+x+x)+(-14+54+20)=300`

`=>3x+60=300`

`=>3x=240`

`=>x=240:3`

`=>x=80`

Vậy `x=80`

` @ \color{yellow}{Le_mon}`

x = 80

x = 80

\(\frac{54\times107-53}{53\times107+54}=\frac{53\times107+107-53}{53\times107+54}=\frac{53\times107+54}{53\times107+54}=1\)

\(\frac{135\times269-134}{134\times269+135}=\frac{134\times269+269-134}{134\times269+135}=\frac{134\times269+135}{134\times269+135}=1\)

K⁰ đ

THAM KHẢO :

A = 53.107 + 54 53 + 1 .107 − 53

= 53.107 + 54 53.107 + 107 − 53

= 53.107 + 54 53.107 + 54 = 1.

B = 134.269 + 135 134 + 1 .269 − 133

= 134.269 + 135 134.269 + 269 − 133

= 134.269 + 135 134.269 + 136 > 1

⇒A < B