quá dễ

a)10.25:(0.2+0.5+0.3)=10.25:10=1.025

b)(0.25x40)5.87=10x5.87=58.7

c)98.45-(41.82+35.63)=98.45-87.45=9

 bạn à mình ko bít lam bài này ai bít là thiên tài

=25-2*5*25+25^2

=(5-25)^2=(-20)^2=400

_10*25=250

10x25=250

10.25=\(\frac{41}{4}\)

10.25 = 10 x 25

\(=\dfrac{1}{4}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{10}+...+\dfrac{1}{2021}-\dfrac{1}{2024}=\dfrac{1}{4}-\dfrac{1}{2024}=\dfrac{505}{2024}\)

\(\dfrac{3}{4.7}+\dfrac{3}{7.10}+\dfrac{3}{10.13}+...+\dfrac{1}{2021.2024}\)

=\(\dfrac{1}{4}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{10}+\dfrac{1}{10}-\dfrac{1}{14}+...+\dfrac{1}{2021}-\)\(\dfrac{1}{2024}\)

=\(\dfrac{1}{4}-\dfrac{1}{2024}\)

=\(\dfrac{505}{2024}\)

\(\dfrac{3}{4.7}+\dfrac{3}{7.10}+\dfrac{3}{10.13}+...+\dfrac{3}{2021.2024}\)

\(=\dfrac{3}{3}.\left(\dfrac{3}{4.7}+\dfrac{3}{7.10}+\dfrac{3}{10.13}+...+\dfrac{3}{2021.2024}\right)\)

\(=1.\left(\dfrac{1}{4}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{10}+\dfrac{1}{10}-\dfrac{1}{13}+...+\dfrac{1}{2021}-\dfrac{1}{2024}\right)\)

\(=1.\left(\dfrac{1}{4}-\dfrac{1}{2024}\right)\)

\(=1.\left(\dfrac{506-1}{2024}\right)\)

\(=1.\dfrac{505}{2024}\)

\(=\dfrac{505}{2024}\)

B = \(\frac{2^{10}.13+2^{10}.65}{2^8.104}=\frac{2^{10}.\left(13+65\right)}{2^8.104}=\frac{2^{10}.78}{2^8.104}\)

B = \(\frac{2^2.39}{52}=\frac{2^2.39}{2^2.13}\)

B = \(\frac{39}{13}\)

B = 3

B = \(\frac{2^{10}.13-2^{10}.65}{2^8.104}=\frac{2^{10}.\left(13+65\right)}{2^{8.104}}=\frac{2^{10}.78}{2^8.104}=\frac{2^2.39}{52}=\frac{2^2.39}{2^2.13}=\frac{39}{13}=3\)

2¹⁰.13+2¹⁰.65/2⁸.104=2¹⁰.(13+65)/2⁸.104=2¹⁰.78/2¹⁰.26=78/26=3

Ta có: 75²⁰ = (5² . 3)²⁰ = 5⁴⁰ . 3²⁰

45¹⁰ . 25¹⁵ = (3² . 5)¹⁰ . (5²)¹⁵ = 3²⁰ . 5¹⁰ . 5³⁰ = 3²⁰ . 5⁴⁰

=> 75²⁰ = 45¹⁰ . 25¹⁵ (= 3²⁰ . 5⁴⁰)

\(\frac{2^{10}.13+2^{10}.65}{28.104}\) đề như vậy hả?

\(\frac{2^{10}.13+2^{10}.65}{28.104}\)=\(\frac{2^{10}.13+2^{10}.5.13}{2^2.7.2^3.13}\)

                                    =\(\frac{2^{10}.13.\left(5+1\right)}{2^2.7.2^3.13}\)

                                  =\(\frac{2^{10}.13.6}{2^5.7.13}\)

                                 =\(\frac{2^5.6}{7}\)

                                =\(\frac{32.6}{7}\)

                               =\(\frac{192}{7}\)

\(\frac{3}{10\cdot13}+\frac{3}{13\cdot16}+...+\frac{3}{58\cdot61}\)

\(=\frac{1}{10}-\frac{1}{13}+\frac{1}{13}-\frac{1}{16}+...+\frac{1}{58}-\frac{1}{61}\)

\(=\frac{1}{10}-\frac{1}{61}\)

\(=\frac{51}{610}\)

\(\frac{3}{10.13}+\frac{3}{13.16}+\frac{3}{16.19}+...+\frac{3}{58.61}\)

\(=\frac{1}{10}-\frac{1}{13}+\frac{1}{13}-\frac{1}{16}+\frac{1}{16}-\frac{1}{19}+...+\frac{1}{58}-\frac{1}{61}\)

\(=\frac{1}{10}-\frac{1}{61}\)

\(=\frac{51}{610}\)

Học tốt !

Gọi S là tổng đó

S=1/10-1/13+1/13-...-1/55+1/58-1/61

S=1/10-1/61=51/610

k đúng cho mk nha