a. \(160 - \left( {{2^3}{{.5}^2} - 6.25} \right)\)

\(\begin{array}{l} = 160 - \left( {8.25 - 6.25} \right)\\ = 160 - 25.\left( {8 - 6} \right)\\ = 160 - 25.2\\ = 160 - 50\\ = 110\end{array}\)

Ta có: 110 = 2.5.11

b. \(37.3 + 225:{15^2}\)

\(\begin{array}{l} = 37.3 + 225:225\\ = 37.3 + 1\\ = 111 + 1\\ = 112\end{array}\)

Ta có: \(112 = 2^4.7\)

c. \(5871:103 - 64:{2^5}\)

\(\begin{array}{l} = 5871:103 - 64:32\\ = 57 - 2 = 55\end{array}\)

Ta có: 55 = 5. 11

d. \(\left( {1 + 2 + 3 + 4 + 5 + 6 + 7 + 8} \right){.5^2} - 850:2\)

\(\begin{array}{l} = \left[ {\left( {1 + 8} \right) + \left( {2 + 7} \right) + \left( {3 + 6} \right) + \left( {4 + 5} \right)} \right]{.5^2} - 850:2\\ = \left( {9 + 9 + 9 + 9} \right){.5^2} - 850:2\\ = {9.4.5^2} - 850:2\\ = {36.5^2} - 425\\ = {36.5^2} - {5^2}.17\\ = {5^2}.\left( {36 - 17} \right)\\ = {5^2}.19=475\end{array}\)

Ta có: \(475 = 5^2.19\)

a: \(160-\left(2^3\cdot5^2-6\cdot25\right)\)

\(=160-\left(8\cdot25-150\right)\)

\(=160-200+150=10=2\cdot5\)

b: \(=111+225:225=112=2^4\cdot7\)

c: \(=57-64:32=57-2=55=5\cdot11\)

d: \(=\left(9\cdot\dfrac{8}{2}\right)\cdot25-425=36\cdot25-425=25=5^2\)

a, * có thể = 0, 1, 2, 4, 5, 6

a. 53

b. 11, 91, 71, 31, 61

c. 157

51

71

151

A= \(4^2.6^3= 4.4.6.6.6\)

\(=(2^2).(2^2).(2.3).(2.3).(2.3)\)

\(=2^{2+2+1+1+1}.3^{1+1+1}=2^7.3^3\)

B =\(9^2.15^2\)

\(=9.9.15.15\)

\(=3^2.3^2.3.5.3.5\)

\(=3^{2+2+1+1}.5^{1+1}\)

=\(3^6.5^2\)

A= 4 2 .6 3 = 4.4.6.6.6 = ( 2 2 ) . ( 2 2 ) . ( 2.3 ) . ( 2.3 ) . ( 2.3 ) = 2 2 + 2 + 1 + 1 + 1 .3 1 + 1 + 1 = 2 7 .3 3 B = 9 2 .15 2 = 9.9.15.15 = 3 2 .3 2 .3 .5 .3 .5 = 3 2 + 2 + 1 + 1 .5 1 + 1 = 3 6 .5 2

chúc bn học tốt

Phân tích các số sau ra thừa số nguyên tố:

a) 120 b) 2500 c) 2436

a: \(120=2^3\cdot3\cdot5\)

b: \(2500=50^2=\left(2\cdot5^2\right)^2=2^2\cdot5^4\)

c: \(2436=2^2\cdot3\cdot7\cdot29\)

a)120=\(2^3\)x3x5

b)2500=\(2^2\)x\(5^4\)

c)2436=\(2^2\)x3x7x29

a: \(51=3\cdot17\)

b: \(84=2^2\cdot3\cdot7\)

Câu 3

Phân tích các số sau ra thừa số nguyên tố:

a) 51=3.17

b) 84=2².3.7

c) 225=3².5²

d) 1800=2².5³.3²

a) 51=3.17

b)84=2.2.3.7

c)225=3.3.5.5

d)2.2.2.3.3.5.5

Bài 2.23

2.24.

\(145=5.29\)

\(310=2.5.31\)

\(2020=2^2.5.101\)

Bài 2.24