Cách 1 : 

(8,5 - 4,3) x 7,4

= 4,2 x 7,4

= 31,08

Cách 2 :

( 8,5 - 4,3) x 7,4

= 8,5 x 7,4 - 4,3 x 7,4

= 62,9 - 31,82

= 31,08

bằng 31.8 nhé bn

Cách 1 : (8,5 - 4,3) x 7,4 = 4,2 x 7,4

                                     = 31,08

Cách 2 : (8,5 - 4,3) x 7,4 = 8,5 x 7,4 - 4,3 x 7,4

                                     = 62,9 - 31,82 

                                     = 31,08

A. 2.9 +6 -4 = 20

B. 8.25 - 6.9 + (-12) = 134

C. -962 + 1548 = 586

D. -85.(36+54) = -85 x 100 = -8500

F. 26.37 - 26.56 - 56.37 + 56.26 =26.37 - 56.37 = 37.(26 - 56)

=37. (-30) = -1100

E. 130 - ( 27 - (36 + 128).2))3

= 130 - ( 27 - 328).3

= 130 - (-301).3

= 130 - (-903)

= 1033

Khóc

a: Ta có: \(\left(8\cdot5^7+5^6-5^5\right):5^5\)

\(=8\cdot5^2+5-1\)

\(=200+4=204\)

b: Ta có: \(\left(9^{30}-27^{19}\right):3^{57}+\left(125^9-25^{12}\right):5^{24}\)

\(=3^{60}:3^{57}-3^{57}:3^{57}+5^{27}:5^{24}-5^{24}:5^{24}\)

\(=27-1+125-1\)

=150

a. (8,5⁷ - 5⁵ + 5⁶) : 5⁵

= (8,5⁷ : 5⁵) - (5⁵ : 5⁵) + (5⁶ : 5⁵)

= 1,7² - 1 + 5

= 2,89 - 1 + 5

= 6,89

b. (9³⁰ - 27¹⁹) : 3⁵⁷ + (125⁹ - 25¹²) : 5²⁴

= (9³⁰ : 3⁵⁷) - (27¹⁹ : 3⁵⁷) + (125⁹ : 5²⁴) - (25¹² : 5²⁴)

= 3³ - 1 + 125 - 1

= 27 - 1 + 125 - 1

= 150

c. (10¹² + 5¹¹ . 2⁹ - 5¹³ - 2⁸) : 4 . 5⁵ . 10⁶

= (10¹² + 2,5 , 10¹⁰ - 5¹³ - 2⁸) : 1,25 . 10¹⁰

= (10¹² : 1,25 . 10¹⁰) + (2,5 . 10¹⁰ : 1,25 . 10¹⁰) - (5¹³ : 1,25 . 10¹⁰) - (2⁸ : 1,25 . 10¹⁰)

= 80 + 2 - \(\dfrac{25}{256}\) - \(\dfrac{1}{48828125}\)

= 81,90234373 \(\approx\) 82

a) Ta có: \(6^6:6^3+4^3\cdot4^3\cdot4^2\)

\(=6^3+4^8\)

\(=216+65536=65752\)

b) Ta có: (-137)+(-129)

=-137-129

=-266

c) Ta có: -84-36

=-(84+36)

=-120

d) Ta có: \(11\cdot37+63\cdot11-49\)

\(=11\cdot\left(37+63\right)-49\)

\(=11\cdot100-49\)

\(=1100-49=1051\)

e) Ta có: \(16:2^3+4:3^3-4\cdot3\)

\(=2^4:2^3+\dfrac{4}{27}-12\)

\(=2+\dfrac{4}{27}-12\)

\(=-10+\dfrac{4}{27}=\dfrac{-270}{27}+\dfrac{4}{27}=\dfrac{-266}{27}\)

\(\frac{7}{4}-\left(\frac{1}{2.2}+\frac{1}{4.3}+\frac{1}{6.4}+\frac{1}{8.5}+\frac{1}{10.6}+\frac{1}{12.7}+\frac{1}{14.8}\right)\div x=0\)

\((\frac{1}{2.2}+\frac{1}{4.3}+\frac{1}{6.4}+\frac{1}{8.5}+\frac{1}{10.6}+\frac{1}{12.7}+\frac{1}{14.8})\div x=\frac{7}{4}\)

\((\frac{1}{4}+\frac{1}{12}+\frac{1}{24}+\frac{1}{40}+\frac{1}{60}+\frac{1}{84}+\frac{1}{112})\div x=\frac{7}{4}\)

\(\left[\frac{1}{2}\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+\frac{1}{42}+\frac{1}{56}\right)\right]\div x=\frac{7}{4}\)

\(\left[\frac{1}{2}\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}+\frac{1}{7.8}\right)\right]\div x=\frac{7}{4}\)

\(\left[\frac{1}{2}\left(1-\frac{1}{8}\right)\right]\div x=\frac{7}{4}\)

\(\left(\frac{1}{2}.\frac{7}{8}\right)\div x=\frac{7}{4}\)

\(\frac{7}{16}\div x=\frac{7}{4}\)

\(x=\frac{7}{16}\div\frac{7}{4}\)

\(x=\frac{7}{16}\times\frac{4}{7}\)

\(x=\frac{1}{4}\)

\(\frac{7}{4}-\left(\frac{1}{2\cdot2}+\frac{1}{4\cdot3}+\frac{1}{6\cdot4}+\frac{1}{8\cdot5}+\frac{1}{10\cdot6}+\frac{1}{12\cdot7}+\frac{1}{14\cdot8}\right)\)

\(=\frac{7}{4}-\left(\frac{1}{4}+\frac{1}{12}+\frac{1}{24}+\frac{1}{40}+\frac{1}{60}+\frac{1}{84}+\frac{1}{112}\right)\)

\(=\frac{7}{4}-\frac{1}{2}\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+\frac{1}{42}+\frac{1}{56}\right)\)

\(=\frac{7}{4}-\frac{1}{2}\left(\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+\frac{1}{4\cdot5}+\frac{1}{5\cdot6}+\frac{1}{6\cdot7}+\frac{1}{7\cdot8}\right)\)

\(=\frac{7}{4}-\frac{1}{2}\left(\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}\right)\)

\(=\frac{7}{4}-\frac{1}{2}\left(1-\frac{1}{8}\right)\)

\(=\frac{7}{4}-\frac{1}{2}\cdot\frac{7}{8}\)

\(=\frac{7}{4}-\frac{7}{16}=\frac{28}{16}-\frac{7}{16}=\frac{21}{16}\)

chết mọe

lm lộn đề r

\(=\dfrac{2^{36}.3^{36}\left(2.5^2.5^{40}-2.5.5^{34}\right)}{2^{30}.3^{30}.5^{30}.2^4.5^4\left(2^2.5^2.3^5.5^5-2^2.3^5\right)}=\dfrac{2^{36}.3^{36}\left(2.5^{42}-2.5^{35}\right)}{2^{34}.3^{30}.5^{34}\left(2^2.3^5.5^7-2^2.3^5\right)}\)

\(=\dfrac{2^2.3^6.2.5^{35}\left(5^7-1\right)}{2^2.3^5\left(5^7-1\right)}=3.2.5^{35}=6.5^{35}\)