1) Ta có: \(\left(-86-x\right)-\left(3+2x\right)=-4-15\)

\(\Leftrightarrow-86-x-3-2x+4+15=0\)

\(\Leftrightarrow-3x-70=0\)

\(\Leftrightarrow-3x=70\)

hay \(x=-\dfrac{70}{3}\)

Vậy: \(x=-\dfrac{70}{3}\)

2) Ta có: \(18+\left(-x\right)-\left(40-28\right)=-32-\left(-18\right)\)

\(\Leftrightarrow18-x-40+28+32-18=0\)

\(\Leftrightarrow-x+20=0\)

\(\Leftrightarrow-x=-20\)

hay x=20

Vậy: x=20

3) Ta có: \(-27-\left(-31+x\right)-25=-5-17\)

\(\Leftrightarrow-27+31-x-25+5+17=0\)

\(\Leftrightarrow-x+1=0\)

\(\Leftrightarrow-x=-1\)

hay x=1

Vậy: x=1

4) Ta có: \(-9-14-x+42-38=-5+13\)

\(\Leftrightarrow-x-19=8\)

\(\Leftrightarrow-x=27\)

hay x=-27

Vậy: x=-27

0.48 x 530 + 0.24 x 156 x 2 + 4 x 314 x 0.12

= 254,4 + 37,44 x 2 + 1256 x 0,12

= 254,4 + 74,88 + 150,72

= 329,28 + 150,72

= 480

0,48 x 530 + 0,24 x 156 x 2 + 4 x 314 x 0,12

= 0,48 x 530 + 0,48 x 156 + 0,48 x 314

= 0,48 x ( 530 + 156 + 314 )

= 0,48 x 1000

= 480

0.48 x 530 +0.24 x 156 x 2 + 4 x 314 x 0.12

= 254.4 + 74.88 + 150.72

= 480

\(=265\left(2+3+2\cdot3\right)-262=265\cdot11-262=2653\)

2653

\(=265\cdot\left(3+2\cdot3\right)-263\cdot3-262=1334\)

= 1334

a) 

5 406 x 2 x 4

= 10 812 x 4 

= 43 248

b) 

370 + 9 826 + 6 530

= 10 196 + 6 530

= 16 726

giải giúp mình với

\(=2568\)

a) 1345 x 37 + 43 x 1345 + 1345 x 18 + 2690

= 1345 x 37 + 43 x 1345 + 1345 x 18 + 1345 x 2

=1345 x (37 + 43 + 18 + 2)

=1345 x 100

=134500

b) (237 x 478 + 45678 : 345) x (23 x 25 - 575)

=(237 x 478 + 45678 : 345) x (575 - 575)

=(237 x 478 + 45678 : 345) x 0

=0 

học tốt em nhé

\(=526+1590-262+795=2649\)