124. 4=500

a, = -500

b,=-500

c,= -500

125. 4=500

a.125. 4 =500

=> (-125). 4= -500

b.125. 4=500

=> (-4). 125= -500

c.125. 4=500

=> 4. (-125) = -500

a) 125 x 25 x 64

= ( 25 x 64 ) x 125

= 1600 x 125 

= 200 000

b) 125 x 25 x 12 x 14

=  ( 125 x 12 ) x ( 25 x 14 )

= 1500 x 350

= 525000

c) 1300 : 50 = 26

d) 700 : 25 = 28

a, = 125 x (25x64)=125 x 1600= 200 000

b, = (125 x 24) x ( 25 x 12) = 3000 x 300 = 900 000

c, 1300 : 50 = 26

d, 700 : 25 = 28.

4 × 125 × 25 × 8

= (4 × 25) × (125 × 8)

= 100 × 1000

= 100 000

2 × 8 × 50 × 25 × 125

= (2 × 50) × (8 × 125) × 25

= 100 × 1000 × 125

= 12 500 000

2 × 3 × 4 × 5 × 50 × 25

= (2 × 50) × (4 × 25) × (3 × 5)

= 100 × 100 × 15

= 150 000

25 × 20 × 125 × 8 - 8 × 20 × 5 × 125

= 8 × 125 × 20 × (25 - 5)

= 1000 × 20 × 20

= 400 000

- (25 x 4) x (125 x8)=100 x 1000 =100000

- (50 x 2) x (8 x 125) x 25=100 x 1000 x 25 =2500000

- (2 x 50 ) x (4 x 25) x (3 x5)=100 x 100 x 15=150000

- 25 x 20 x125 x 8 - 5

= (20 x 5) x (125 x 8) -25=100 x 1000 -5 =100000 - 5 =99995

a) \(A=125\left(-24\right)+24.225\)

\(=24\left[\left(-125\right)+225\right]\)

\(=24.100=2400\)

b) \(B=26\left(-125\right)-125\left(-36\right)\)

\(=125\left[\left(-26\right)-\left(-36\right)\right]\)

\(=125.10=1250\)

c) \(C=25\left(75-45\right)-75\left(45-25\right)\)

\(=25.75-25.45-75.45-75.25\)

\(=\left(25.75-75.25\right)-25.45-75.45\)

\(=-25.45-75.45\)

\(=45\left(-25-75\right)\)

\(=45\left(-100\right)=-4500\)

Bài 10:

a: x-5=-1

=>x=-1+5

=>x=4

b: x+30=-4

=>x=-4-30

=>x=-34

c: x-(-24)=3

=>x+24=3

=>x=3-24

=>x=-21

d: 22-(-x)=12

=>22+x=12

=>x=12-22

=>x=-10

e: (x+5)+(x-9)=x+2

=>x+5+x-9=x+2

=>2x-4=x+2

=>2x-x=4+2

=>x=6

f: (27-x)+(15+x)=x-24

=>x-24=27-x+15+x=42

=>x=42+24

=>x=66

Bài 9:

a: 15-(4-x)=6

=>4-x=15-6=9

=>x=4-9=-5

b: -30+(25-x)=-1

=>-30+25-x=-1

=>-5-x=-1

=>x+5=1

=>x=1-5

=>x=-4

c: x-(12-25)=-8

=>x-(-13)=-8

=>x+13=-8

=>x=-8-13

=>x=-21

d: (x-29)-(17-38)=-9

=>x-29-(-21)=-9

=>x-29+21=-9

=>x-8=-9

=>x=-9+8

=>x=-1

Bài 8:

a: (17-229)+(17-25+229)

=17-229+17-25+229

=34-25

=9

b: (125-679+145)-(125-679)

=125-679+145-125+679

=145

2267?7424