\(A=\frac{7.9+14.27+21.36}{21.27+42.81+63.108}\)

\(A=\frac{7.9+7.2.9.3+7.3.9.4}{21.27+21.2.27.3+21.3.27.4}\)

\(A=\frac{7.9.\left(1+2.3+3.4\right)}{21.27+\left(1+2.3+3.4\right)}\)

\(A=\frac{7.9}{3.7.3.9}\)

\(A=\frac{1}{3.3}=\frac{1}{9}\)

Rút gọn tử số và mẫu số, ta được:
1.1+1.1+1.1/3.3+3.3+3.3
=1.3/9.3
Rút gọn 3 trên tử với 3 dưới mẫu
Vậy A=1/9

Tick nhé 

alo làm giống vcl

Ta có:

\(\frac{7.9+14.27+21.36}{21.27+42.81+63.108}\)

\(=\frac{7.9+14.27+21.36}{7.3.9.3+14.3.27.3+21.3.36.3}\)

\(=\frac{7.9+14.27+21.36}{\left(.9+14.27+21.36\right).3.3}\)

\(=\frac{7.9+14.27+21.36}{\left(7.9+14.27+21.36\right).9}\)

\(=\frac{1}{9}\)

cảm ơn bạn đã giúp tui bài này

1ohaan n9

A = \(\frac{7.9+2.7.3.9-3.7.4.9}{3.7.3.9+2.3.7.9.9+7.9.4.3.9}\)

= \(\frac{7.9.\left(1+6-12\right)}{3.7.9.\left(3+18+36\right)}=\frac{-5}{3.57}=\frac{-5}{171}\)

sai roi

alo làm bài cô tú à

Ta có:A=\(\frac{7.9.\left(1+2.3+3.4\right)}{21.27.\left(1+2.3+3.4\right)}=\frac{7.9}{21.27}=\frac{1}{9}\)

Vậy A=\(\frac{1}{9}\)

kết quả là 1/9

\(A=\frac{7.9+14.27+21.36}{21.27+42.81+63.108}\)

\(A=\frac{7.9+7.2.27+7.3.36}{7.3.27+7.6.81+7.9.108}\)

\(A=\frac{7.9+7.54+7.108}{7.81+7.486+7.972}\)

\(A=\frac{7.\left(9+54+108\right)}{7.\left(81+486+972\right)}\)

\(A=\frac{7.171}{7.1539}=\frac{171}{1539}=\frac{1}{9}\)

7255/21198

Chúc bạn học tốt

dấu < này nè chắc vậy thui kick tớ nhe

1/3

A = \(\dfrac{7.9+14.27+21.36}{21.27+42.81+63.108}\)

= \(\dfrac{7.9+7.2.9.3+7.3.9.4}{21.27+21.2.27.3+21.3.27.4}\)

= \(\dfrac{\left(7.9\right)\left(2.3+3.4\right)}{\left(21.27\right)\left(2.3+.3.4\right)}\)

= \(\dfrac{1}{9}\)

@Nguyễn Ngọc Gia Hân