x=\(\dfrac{35}{6}\)

$x/25=-3/15.7/6$

$=>x/25=-7/30$

$=>x=-7/30.25$

$=>x=-35/6$

(\(\frac{25}{5^2}\times30\)) : 15 x 7

= (1 x 30) : 15 x 7

= 30 : 15 x 7

= 2 x 7

= 14

mn giúp mình nha

12
−
{
800
:
[
537
−
(
2
5
+
15.7
)
]
}
.1
2021
12
−
{
800
:
[
537
−
(
2
5
+
15.7
)
]
}
.1
2021

=
12
−
{
800
:
[
537
−
(
32
+
105
)
]
}
=
12
−
[
800
:
(
537
−
137
)
]
=
12
−
(
800
:
400
)
=
12
−
2
=
10
=
12
−
{
800
:
[
537
−
(
32
+
105
)
]
}
=
12
−
[
800
:
(
537
−
137
)
]
=
12
−
(
800
:
400
)
=
12
−
2
=
10

\(=12-32\cdot\left\{800:407\right\}=12-32\cdot\dfrac{800}{407}=\dfrac{-20716}{407}\)

Sửa đề: \(12-800:\left\lbrace537-\left\lbrack537-\left(2^5+15\cdot7\right)\right\rbrack\right\rbrace-1^{2021}\)

Ta có: \(12-800:\left\lbrace537-\left\lbrack537-\left(2^5+15\cdot7\right)\right\rbrack\right\rbrace-1^{2021}\)

\(=12-800:\left\lbrace537-537+\left(2^5+15\cdot7\right)\right\rbrace-1^{2021}\)

\(=12-800:\left\lbrace\left(2^5+15\cdot7\right)\right\rbrace-1^{}\)

\(=11-\frac{800}{32+105}=11-\frac{800}{137}=\frac{707}{137}\)

\(=3\)

2,07+ 4,15 +17,93 +5,85= 30

2,07 + 4,15 + 17,93 + 5,85

= ( 2,07 + 17,93 ) +  ( 4,15 + 5,85 )

=20 + 10

=30