5.6+2.3=7.9

3.4-2.6=0.8

1.1+2.2=3.3

ai qua nhớ k mình nhé

5.6+2.3

= 30+6

=36

3.4-2.6

=12-12

=0

1.1+2.2

=1+4

=5

đồ ngu!
 

A=1.5+2.6+3.7+...+20.24

A=1.(2+3) + 2.(3+3) + 3.(4+3) + ... + 20.(21+3)

A=1.2+3 + 2.3 +6 + 3.4 +9 + ... + 20.21 + 60

A= (1.2+2.3+3.4+...+20.21) + (3+6+9+...+60)

Tính B= 1.2 + 2.3 + 3.4 +...+ 20.21

3.B= 1.2.3 + 2.3.3 + 3.4.3 +...+ 20.21.3

3B= 1.2.3 + 2.3.(4-1) + 3.4. (5-2) + ... + 20.21. (22-19)

3B= 20.21.22 suy ra B= 3080

Tính 3+6+9+...+60= [(60-3):3+1](3+60):2=630

Vậy A= 3080 + 630=3710

Đặt S= 1.2 + 2.3 + 3.4 + ...+ 99.100
 3S = 1.2.3+2.3.3+3.4.3+...+98.99.3+99.100.3
3S= 1.2.3+2.3(4-1)+3.4(5-2)+...+98.99(100-97)+99.100(101-98)
3S= 1.2.3+2.3.4-1.2.3+3.4.5-2.3.4+...-97.98.99+99.100.101-98.99.100
3S = 99.100.101  3S = 3.33.100.101 
 S=33.100.101= 333300

Đặt

S= 1.2 + 2.3 + 3.4 + ...+ 99.100  

3S = 1.2.3+2.3.3+3.4.3+...+98.99.3+99.100.3

3S= 1.2.3+2.3(4-1)+3.4(5-2)+...+98.99(100-97)+99.100(101-98)

3S= 1.2.3+2.3.4-1.2.3+3.4.5-2.3.4+...-97.98.99+99.100.101-98.99.100

3S = 99.100.101  3S = 3.33.100.101  

S=33.100.101= 333300

= -14/13

a. \(5,6\times2+2,8\times8+11,2\times2-48,5 \)

\(=5,6\times2+2,8\times4\times2+11,2\times2-48,5\)

\(=11,2\times1+11,2\times2+11,2\times2-48,5\)

\(=11,2\times\left(1+2+2\right)-48,5\)

\(=11,2\times5-48,5\)

\(=56-48,5\)

\(=7,5\)

b. \(0,8\times96+1,6\times2\)

= \(0,8\times96+0,8\times4\)

\(=0,8\times\left(96+4\right)\)

\(=0,8\times100\)

\(=80\)

Chúc cậu học tốt và nhớ thực hiện lời hứa với mình đó =)))))))

Ta có: \(B=\frac{5^2.6^{11}.16^2+6^2.12^6.15^2}{2.6^{12}.10^4-81^2.960^3}=\frac{5^2.\left(2.3\right)^{11}.\left(4^2\right)^2+\left(2.3\right)^2.\left(2^2.3\right)^6.\left(3.5\right)^2}{2.\left(2.3\right)^{12}.\left(2.5\right)^4-\left(3^4\right)^2.\left(2^6.3.5\right)^3}\)

\(\frac{5^2.2^{11}.3^{11}.2^8+2^2.3^2.2^{12}.3^6.3^2.5^2}{2.2^{12}.3^{12}.2^4.5^4-3^8.2^{18}.3^3.5^3}=\frac{5^2.2^{19}.3^{11}+2^{14}.3^{10}.5^2}{2^{17}.3^{12}.5^4-3^{11}.2^{18}.5^3}\)

\(=\frac{5^2.2^{14}.3^{10}.\left(2^5.3+1\right)}{2^{17}.3^{11}.5^3.\left(3.5-2\right)}=\frac{2^{14}.3^{10}.5^2.97}{2^{17}.3^{11}.5^3.13}=\frac{1.1.1.97}{2^3.3.5.13}=\frac{97}{1560}\)

\(B=\frac{5^2.6^{11}.16^2+6^2.12^6.15^2}{2.6^{12}.10^4-81^2.960^3}\)

\(B=\frac{5^2.2^{11}.3^{11}.2^{4^2}+2^2.3^2.2^{2^6}.3^6.3^2.5^2}{2.2^{12}.3^{12}.10^4-3^{4^2}.2^{5^3}.3^3}\)

\(B=\frac{5^2.2^{11}.2^8.3^{11}+2^2.2^{12}.3^2.3^6.3^2.5^2}{2^{13}.3^{12}.10^4-3^8.3^3.2^{15}}\)

\(B=\frac{5^2.2^{19}.3^{11}+2^{14}.3^{10}.5^2}{2^{13}.3^{12}.10^4-3^{11}.2^{15}}\)

\(B=\frac{5^2.2^{14}.3^{10}.\left(2^5.3+1\right)}{2^{13}.3^{11}.\left(3.10^4-2^2\right)}\)

\(B=\frac{5^2.2^{14}.3^{10}.97}{2^{13}.3^{11}.29996}\)

\(B=\frac{5^2.2.97}{3.29996}\)

\(B=\frac{4850}{89988}\)

\(B=\frac{2425}{44994}\)

leminhduc giải sai rồi

Mình nhìn vào cách làm đã biết rồi

Kết quả không đúng đâu

C=49/50