a) 125.3+125.125.6

=125.3+125.750

=125.(3+750)

=125.753

=94125

b) (245.99+245)-(145.101-145)

=(245.(99+1))-(145.(101-1))

=245.100-145.100

=(245-145).100

=100.100

=10000

c) 154.(28+52)-45.(26+54)

=154.80-45.80

=(154-45).80

=109.80

=8720

a) 125x3+125+125x6

=125x(3+1+6)

=125x10

=1250

b) (245x99+245)-(145x101-145)

=(245x99+245)-(145x100)

=(245x100)-14500

=24500-14500

10000

c) 154x80-45x80

=80x(145-45)

=80x100

=8000

a, 125 x 3 + 125 x 125 x 6

=125 x 3 + 125 x 750

=125 x( 3+750)

=125 x753

=94125

b, ( 245 x 99 + 245 ) - ( 145 x 101 - 145 )

=[245 x ( 99+1 )] - [145 x ( 101-1 )]

=( 245 x 100 ) - ( 145 x 100 )

=24500 - 14500

=10 000

c, 154 x ( 28 + 52 ) - 45 x ( 26 + 54 )

=154 x 80 - 45 x 80

=(154-45)x80

=109 x80

=8720

3145-246+2347-145+4246-347

=(3145-145)+(2347-347)+(4246-246)

=3000+2000+4000=9000

minh chi lam dk câu ý thui

Mình ko biết làm vì mình lớp ??????

\(312\times425+312\times574+312\)

\(=312\times\left(425+574+1\right)\)

\(=312\times1000\)

\(=312000\)

312 × 425 + 312 × 574 + 312

= 312 × (425 + 574 + 1)

= 312 × 1000

= 312000

312x425+312x574+312x1

=312x(425+574+1)

=312x1000

=3120000

\(\text{30.(x+2)-6.(x+5)-24x=100}\)

\(30x+60-6x-30-24x=100\)

\(30x-6x-24x=100+30-60\)

\(0=70\\ \Rightarrow x\in\varnothing\)

\(\text{-12.(x-15)+7.(3-x)=15}\)

\(-12x+180+21-7x=15\)

\(-12x-7x=15-21-180\)

\(-19x=-186\)

\(x=\frac{186}{19}\)

\(\text{-(574+x)=(x-12-741)-23}\)

\(-574-x=x-12-741-23\)

\(-x-x=-752+574\)

\(-2x=-178\)

\(x=89\)

chúc bạn học tốt !!!

cảm ơn Nguyễn ngọc linh nhiều nha 

\(x+\frac{145}{245}=\frac{52}{70}\)

\(\Leftrightarrow x+\frac{29}{49}=\frac{26}{35}\)

\(x=\frac{26}{35}-\frac{29}{49}\)

\(x=\frac{182}{245}-\frac{145}{245}\)

\(x=\frac{37}{245}\)

x+145/245 =52/70 

⇔x+29/49 =26/35 

x=26/35 −294/9 

x=182/245 −145/245 

x=37/245 

245*(3-7+14)

=245*10

=2450

= 245 x (3+14-7)

= 245 x 10

= 2450

43701630

156x258=40248

245x78=19110

mk kb rồi đó

156 x 258 = 40248

245 x 78 = 19110

Trả lời:

156 x 258 = 40248

245 x 78 = 19110

679+679x123-679x24

=679x1+679x123+679x24

=679x(1+123-24)

=679x100

=67900

245x327-245x18-9x245

=245x(327-18-9)

=245x300

=73500

679 +679 x 123 - 679 x 24

= 679 x ( 1 + 123 - 24 ) 

= 679 x 100

= 67900

245 x 327 - 245 x 18 - 9 x 245

= 245 x ( 327 - 18 - 9 ) 

= 245 x 300

= 73500

679+679x123-679x24

=679x1+679x123-679x24

=679x(1+123-24)

=679x100

=67900

245x327-245x18-9x245

=245x(327-18-9)

=245x300

=73500