5=25

=25

5 = 25

a)  5 6 + 1 6 ≤ x ≤ 13 4 + 14 8 ⇔ 1 ≤ x ≤ 5 ⇔ x ∈ 1 ; 2 ; 3 ; 4 ; 5

b)  − 5 6 + 8 3 + 29 − 6 ≤ x ≤ − 1 2 + 2 + 5 2 ⇔ − 3 ≤ x ≤ 4 ⇔ x ∈ − 3 ; − 2 ; − 1 ; 0 ; 1 ; 2 ; 3 ; 4

c)  79 15 + 7 5 + − 8 3 ≤ x ≤ 10 3 + 15 4 + 23 12 ⇔ 4 ≤ x ≤ 9 ⇔ x ∈ 4 ; 5 ; 6 ; 7 ; 8 ; 9

a, 386 154 + 260 765

b, 726 485 – 52 936

c, 308 × 563

d, 5 176 : 35

a) 646919 

b) 673549

c) 173404

d) 147 (dư 31)

5x84=420

12x35=420

7x22=154

11x14=154

2x77=154

5.x=420

x=420:5

x=84

12.x=420

x=420:12

x=35

7.x=154

x=154:7

x=22

11.x=154

x=154:11

x=14

2.x=154

x=154:2

x=77

5 x 84 = 420

12 x 35 = 420

7 x22 = 154

11 x 14 = 154 

2 x 77 = 154

a) \(103^2=\left(100+3\right)^2=10000+600+9=10609\)

b) \(52\cdot48=\left(50-2\right)\left(50+2\right)=2500-4=2496\)

c) \(75^2-50\cdot75+25^2=\left(75-25\right)^2=50^2=2500\)

\(103^2=\left(100+3\right)^2=100^2+2.3.100+3^2=10000+600+9=10609\)

\(52.48=\left(50+2\right)\left(50-2\right)=50^2-2^2=2500-4=2496\)

\(75^2-50.75+25^2=75^2-25.75-25.75+25^2=75\left(75-25\right)-25\left(75-25\right)=\left(75-25\right)=50^2=2500\)

1. 14,23 + 7,06 + 1,77​

= ( 14,23 + 1,77) + 7,06

= 16 + 7,06

= 23,06

2. 13,7 * 48 + 52 * 13,7

= 13,7 * (48 + 52)

= 13,7 * 100

=1370

3. làm tương tự như câu 2

Trả lời:

\(a,\)\(14,23+7,06+1,77\)

\(=\left(14,23+1,77\right)+7,06\)

\(=16+7,06\)

\(=23,06\)

\(b,\)\(13,7.48+52.13,7\)

\(=13,7.\left(48+52\right)\)

\(=13,7.100\)

\(=1370\)

\(c,\)\(15,58.43+15,58+56.15,58.103-15,05-2.15,58\)

\(=15,58.\left(43+1+5768-2\right)-15,05\)

\(=15,58.5810-15,05\)

\(=90519,8-15,05\)

\(=90504,75\)

Hok tốt!

Good girl

=(14,23+1,77)+7,06

=15+7,06

=22,06

=13,7*(48+52)

=13,7*100

=1370

a. 646 919

b. 673549

c. 173 404

d. 35 dư 3

a. 646 919

b. 673549

c. 173 404

d. 35 dư 3