a) 17. 85 + 15 . 17 = 300

= 17. 9 85 = 15) + 300

= 2000

b) 72. 121 + 27 .121 = 121

= 121 . ( 72 + 27 = 1)

= 12100

c) 32. 39 + 52 . 21 - 12 . 39 + 21 . 48

= ( 32 - 12).39 + 21. ( 52 + 48)

= 2880

d) 47 - ( 45.24 - 52.12) : 14

= 47 - ( 45 . 16 - 25.12) : 14

= 17

e) 102 - 60 : ( 54 : 52 - 3. 5)

= 100 - 60 : ( 25 - 15)

= 100 - 6

= 94

17.85 + 15.17 - 120 

= 1445 + 255 -120 

=1700 - 120  

=1580 

a/17.85+15.17-120

=120.[(17-17).(85+15)]

=120.          0

=0

17.85+15.17-120

=[85+15].17-120

=100.17-120

=1700-120

=1480

Lời giải:

$=17.85+15.17-2^{45}=17(85+15)-2^{45}=17.100-2^{45}$

$=1700-2^{45}$

Số $2^{45}$ quá lớn để hiển thị nên để kết quả như trên là hợp lý nhất rồi bạn.

\(=200-100:5+1\)

\(=200-20+1\)

=\(180+1\)

\(=181\)

181

5: =5/7(5/11+2/11-14/11)

=5/7*(-7/11)

=-5/11

6: =-5/4(2/11+9/11)+1+3/4

=7/4-5/4=1/2

7: =-5/7(3/13+10/13)+1+5/7

=1

8: =7/4(29/5-9/5)+3+2/13

=3+2/13+7/4*4

=10+2/13

=132/13

c: \(=\left(\dfrac{3}{5}+\dfrac{83}{200}-\dfrac{3}{200}\right)\cdot\dfrac{8}{3}\cdot\dfrac{1}{4}=\dfrac{8}{3}\cdot\dfrac{1}{4}=\dfrac{2}{3}\)

g: \(=\dfrac{1}{2}\cdot\dfrac{4}{3}\cdot\dfrac{3}{4}\cdot\dfrac{5}{2}+\dfrac{3}{5}=\dfrac{5}{4}+\dfrac{3}{5}=\dfrac{25+12}{20}=\dfrac{37}{20}\)

c) = 2/3

g) = 37/20 = 1,85

n) = 3/17

e: \(=\dfrac{21-6}{8}\cdot\dfrac{16}{3}=\dfrac{15}{3}\cdot2=10\)

f: \(=\dfrac{-3\cdot3+7\cdot4}{12}:\dfrac{2\cdot2-5\cdot9}{18}\)

\(=\dfrac{19}{12}\cdot\dfrac{18}{-41}=\dfrac{-57}{82}\)

g: \(=\dfrac{9-8}{10}\cdot\dfrac{5}{2}+1=\dfrac{1}{10}\cdot\dfrac{5}{2}+1=\dfrac{1}{4}+1=\dfrac{5}{4}\)

o: \(=\dfrac{3}{4}\cdot\left[\dfrac{1}{5}-\dfrac{4}{7}-\dfrac{3}{5}\cdot\dfrac{-5}{7}\right]=\dfrac{3}{4}\cdot\left(\dfrac{1}{5}-\dfrac{4}{7}+\dfrac{3}{7}\right)\)

\(=\dfrac{3}{4}\cdot\left(\dfrac{1}{5}-\dfrac{1}{7}\right)=\dfrac{3}{4}\cdot\dfrac{2}{35}=\dfrac{3}{70}\)

p: \(=\left[\left(\dfrac{1}{9}\cdot\dfrac{27}{8}\right)\cdot3\right]\cdot\dfrac{-128}{81}=\dfrac{9}{8}\cdot\dfrac{-128}{81}=\dfrac{-16}{9}\)