=6+4x6+6x10+(7x2)x213x5+(7x3)x35

=6x(1+10+4)+7x2130+7x105

=6x15+7x(2130+105)

=90+7x2235

=90+15645

=15735

15735

mình viết nhàm đeài các bạn trả lời bài khác nhé

Giải:

a) \(\dfrac{5^3.90.4^3}{25^2.3^2.2^{13}}\) 

\(=\dfrac{5^3.5.3^2.2.\left(2^2\right)^3}{\left(5^2\right)^2.3^2.2^{13}}\) 

\(=\dfrac{5^4.3^2.2.2^6}{5^4.3^2.2^{13}}\) 

\(=\dfrac{5^4.3^2.2^7}{5^4.3^2.2^{13}}\) 

\(=\dfrac{1}{2^6}=\dfrac{1}{64}\) 

b) \(\dfrac{15^2.16^4-15^3.16^3}{12^2.20^3-20^2.12^3}\) 

\(=\dfrac{15^2.16^3.16-15^2.16^3.15}{12^2.20^2.20-20^2.12^2.12}\) 

\(=\dfrac{15^2.16^3.\left(16-15\right)}{12^2.20^2.\left(20-12\right)}\) 

\(=\dfrac{\left(3.5\right)^2.\left(2^4\right)^3.1}{\left(3.2^2\right)^2.\left(2^2.5\right)^2.8}\) 

\(=\dfrac{3^2.5^2.2^{12}}{3^2.\left(2^2\right)^2.\left(2^2\right)^2.5^2.2^3}\) 

\(=\dfrac{3^2.5^2.2^{12}}{3^2.5^2.2^4.2^4.2^3}\) 

\(=\dfrac{3^2.5^2.2^{12}}{3^2.5^2.2^{11}}\) 

\(=2\) 

c) \(\dfrac{2.3+4.6+14.21}{3.5+6.10+21.35}\) 

\(=\dfrac{2.3+2.3.2.2+2.3.7.7}{3.5+3.5.2.2+3.5.7.7}\) 

\(=\dfrac{2.3+2.3.4+2.3.49}{3.5+3.5.4+3.5.49}\) 

\(=\dfrac{2.3.\left(1+4+49\right)}{3.5.\left(1+4+49\right)}\) 

\(=\dfrac{2.3}{3.5}\) 

\(=\dfrac{2}{5}\) 

Chúc bạn học tốt!

\(\frac{2.3.\left(1+2.3+7.7\right)}{3.5.\left(1+2.3+7.7\right)}=\frac{2}{5}\)

a=2

b=2/5

a=2

b=2\5 đó bạn

\(\frac{2.3+4.6+14.21}{3.5+6.10+21.35}=\frac{2.3+8.3+98.3}{3.5+3.20+3.45}=\frac{3.\left(2+8+98\right)}{3.\left(5+20+45\right)}=\frac{108}{70}=\frac{54}{35}=1\frac{19}{35}\)

rút gọn PS

3.7.13.37.39-10101/505050-70707

làm bài dưới :

rút gọn phân số : 

\(\frac{3.7.13.37.39-10101}{505050-70707}\)

\(=\frac{10101.39-10101}{50.10101-7.10101}\)

\(=\frac{10101.\left(39-1\right)}{10101.\left(50-7\right)}\)

\(=\frac{38}{43}\)

2.3+4.6+14.21/3.5+6.10+21.35

= 2 . 3 + 2 . 2 . 3 . 2 + 7 .

\(\frac{2\cdot3+4\cdot6+14\cdot21}{3\cdot5+6\cdot10+21\cdot35}\)=\(\frac{2\cdot3\cdot\left(1+2\cdot2+7\cdot7\right)}{3\cdot5\cdot\left(1+2\cdot2+7\cdot7\right)}\)

Sau đó ta chia tử và mẫu cho (1+2*2+7*7) thì ta có phân số

\(\frac{2\cdot3}{3\cdot5}\)=\(\frac{2}{5}\)(rút gọn tử và mẫu cho 3)

..............

\(\frac{2.3+4.6+14.21}{3.5+6.10+21.35}=\frac{2.3+4.6+2.7.3.7}{3.5+2.3.5.2+3.7.5.7}\)

\(=\frac{6.1+4.6+6.49}{15.1+15.4+15.49}\)

\(=\frac{6\left(1+4+49\right)}{35\left(1+4+49\right)}=\frac{6}{35}\)

tren tu : dat 2.3 ra ngoai

trong ngoặc: 1+2.2+7.7

dưới mẫu : dat 3.5 ra ngoai

trong ngoặc: 1+2.2+7.7

rút gọn: 2.3/3.5=2/5

cho mk vs

=-1

=2/5

=38/43

= 3/2

\(\frac{2.3+4.6+14.21}{3.5+6.10+21.3.5}\)

\(=\frac{2+2+7}{5+5+4}\)

\(=\frac{11}{14}\)

BÀI TÍP THEO TÁCH RA RỒI RÚT GỌN NHA MK BẬN RÒI