a, ta có \(\frac{2.\left(-13\right).9.10}{\left(-3\right).4.\left(-5\right).26}\)=\(\frac{2.\left(-13\right).\left(-3\right).\left(-3\right).2.\left(-5\right)}{\left(-3\right).2.2.\left(-5\right).\left(-2\right).\left(-13\right)}\)

rút gọn đi còn: \(\frac{-3}{-2}\)=\(\frac{3}{2}\)

15×8+15×4/12×3

= 15×(8+4)/12×3

=15×12/12×3

=15/3

=5

a, Ta có cách làm sau

\(\dfrac{15.8+15.4}{12.3}=\dfrac{15.\left(8+4\right)}{12.3}=\dfrac{15.12}{12.3}=\dfrac{3.5.12}{12.3}\)

\(=\dfrac{5}{1}=5\)

b,

\(\dfrac{2.\left(-13\right).9.10}{-3.4.\left(-5\right).26}\)=\(\dfrac{2.\left(-13\right).\left(-3\right).\left(-3\right).\left(-2\right).\left(-5\right)}{-3.2.2_{ }.\left(-5\right).\left(-2\right).\left(-13\right)}\)=\(\dfrac{-3}{2}\)

a, \(\frac{7.25-49}{7.24+21}\)

\(=\frac{7.25-7.7}{7.24+7.3}=\frac{7\left(25-7\right)}{7\left(24+3\right)}=\frac{18}{27}=\frac{2}{3}\)

b, \(\frac{2.\left(-13\right).9.10}{\left(-3\right).4.\left(-5\right).26}=\frac{2.\left(-13\right).\left(-3\right).\left(-3\right).\left(-5\right).\left(-2\right)}{\left(-3\right).2.2.\left(-5\right).\left(-13\right).\left(-2\right)}\)

\(=\frac{-3}{2}\)

DỄ LẮM !

a) \(\frac{7\cdot25-49}{7\cdot24+21}=\frac{7\cdot25-7\cdot7}{7\cdot24+7\cdot3}=\frac{7\left(25-7\right)}{7\left(24+3\right)}\)

=\(\frac{18}{27}=\frac{2}{3}\)

b) \(\frac{2\cdot\left(-13\right)\cdot9\cdot10}{\left(-3\right)\cdot4\cdot\left(-5\right)\cdot26}=\frac{-1\cdot2\cdot13\cdot3\cdot3\cdot5\cdot2}{1\cdot3\cdot2\cdot2\cdot5\cdot13\cdot2}=-\frac{3}{2}\)

Chúc bn học tốt !

\(\frac{2.\left(-13\right).9.10}{-3.4.\left(-5\right).26}=\frac{2.\left(-13\right).\left(-3\right).\left(-3\right).\left(-5\right).\left(-2\right)}{-3.2.2.\left(-5\right).\left(-13\right).\left(-2\right)}=\frac{-3}{2}\)

Bạn tự trực tiêu các số bằng nhau nha

Chúc học tốt!

\(\frac{2.\left(-13\right).9.10}{-3.4.\left(-5\right).26}\)

\(=\frac{1.\left(-1\right).3.2}{-1.2.\left(-1\right).2}\)

\(=\frac{-6}{4}=\frac{-3}{2}\)

Vậy phân số \(\frac{2.\left(-13\right).9.10}{-3.4.\left(-5\right).26}\) rút gọn là \(\frac{-3}{2}\)

\(a.\frac{2\cdot\left(-13\right)\cdot9\cdot10}{\left(-3\right)\cdot4\cdot\left(-5\right)\cdot26}\)

\(=\frac{2\cdot\left(-13\right)\cdot3\cdot3\cdot2\cdot5}{\left(-3\right)\cdot2\cdot2\cdot\left(-5\right)\cdot13\cdot2}\)

\(=-\frac{3}{2}\)

b) \(\frac{2^3\cdot3^4}{2^2\cdot3^2\cdot5}=\frac{2\cdot3^2}{5}=\frac{2\cdot9}{5}=\frac{18}{5}\)

\(\frac{2^4\cdot5^2\cdot11^2\cdot7}{2^3\cdot5^3\cdot7^2\cdot11}=\frac{2\cdot1\cdot11\cdot1}{1\cdot5\cdot7\cdot1}=\frac{22}{35}\)

c) \(\frac{121\cdot75\cdot130\cdot169}{39\cdot60\cdot11\cdot198}=\frac{11\cdot11\cdot13\cdot10\cdot169}{13\cdot3\cdot6\cdot10\cdot11\cdot11\cdot6\cdot3}\)

\(=\frac{169}{3\cdot6\cdot6\cdot3}=\frac{169}{324}\)

d) \(\frac{1998\cdot1990+3978}{1992\cdot1991-3984}\)

=\(\dfrac{1.\left(-1\right).\left(-3\right).\left(-2\right)}{1.2.1.2}\)

\(=\dfrac{-6}{4}\)

\(=-\dfrac{3}{4}\)

\(=\frac{1}{3^2}=\frac{1}{9}\)

\(\frac{3^{10}.\left(-5\right)^{21}}{\left(-5\right)^{21}.3^{12}}\)\(=\)\(\frac{1}{3^2}\)\(=\frac{1}{9}\)