Question

rút gọn các phân số sau
 a, 2^3 . 3^4/ 2^2 . 3^2 . 5
b, 2^4 . 5^2  . 11^2 .7 / 2^3 . 5^3 . 7^2 .11
c, 1998.1990+3978 / 1992 . 1991 - 3984

Answer 1

Chúc học tốt!!!!

Answer 2

a,\(\frac{2^3.3^4}{2^2.3^2.5}=\frac{2.3^2}{5}=\frac{2.9}{5}=\frac{18}{5}\)

b, \(\frac{2^4.5^2.11^2.7}{2^3.5^3.7^2.11}=\frac{2.11}{5.7}=\frac{22}{35}\)

c,\(\frac{1998.1990+3978}{1992.1991-3984}=\frac{18.111.1990+18.221}{24.83.1991-166.24}\)

                                           \(=\frac{18.\left(111.1990+221\right)}{24.\left(83.1991-166\right)}\)

                                           \(=\frac{3.221111}{4.165087}=\frac{221111}{4.55029}=\frac{221111}{220116}\)

                                           \(\)

Answer 3

a) 2^3 . 3^4/2^2 . 3^2 . 5

= 8 . 81/4 . 9 . 5 

=7290

c) \(\frac{1998.1990+3978}{1992.1991-3984}\)

= \(\frac{1998.1990+1998.2}{1992.1991-1992.2}\)

=\(\frac{1998.\left(1990+2\right)}{1992.\left(1991-2\right)}\)

= \(\frac{1998.1992}{1992.1989}\)

= \(\frac{1998}{1989}\)

Answer 4

3978=1989.2 mà bạn Thùy Phương