1/4

\(=\dfrac{8}{15}\left(\dfrac{25}{32}-\dfrac{10}{32}\right)=\dfrac{8}{15}\cdot\dfrac{15}{32}=\dfrac{1}{4}\)

( 25/32 - 10/32) x 8/15

 = 15/32 x 8/15

= 1/4

\(=\dfrac{-15}{8}\times\dfrac{8}{-15}-\dfrac{15}{8}\times\dfrac{32}{27}-\dfrac{15}{7}\\=1-\dfrac{20}{9}-\dfrac{15}{7}\\ =\dfrac{1\times9\times7-20\times7-15\times9}{63}=\dfrac{-212}{63}\)

\(\dfrac{-15}{8}\) x \(\left(\dfrac{8}{15}+\dfrac{32}{27}\right)\) 

= \(\dfrac{-15}{8}\) x \(\dfrac{232}{135}\) 

= \(\dfrac{-29}{9}\)

\(\dfrac{-15}{8}\)*\(\left(\dfrac{8}{15}+\dfrac{32}{27}\right)\)

=\(\dfrac{-15}{8}\)*\(\left(\dfrac{216+480}{405}\right)\)

=\(\dfrac{-15}{8}\)*\(\dfrac{696}{405}\)= \(\dfrac{-15}{8}\)*\(\dfrac{232}{135}\)= \(\dfrac{\left(-15\right)\cdot232}{8\cdot135}\)= \(\dfrac{\left(-1\right)\cdot29}{1\cdot9}\)= \(\dfrac{-29}{9}\)

15 x 5 x 3 x ( 18 x 32 - 8 x 32 - 10 x 32 )

= 15 x 5 x 3 x { 18 - 8 - 10 } x 32 }

= 15 x 5 x 3 x 0

= 0 

Vì số nào nhân với 0 cx bằng 0 

15 x 5 x 3 x ( 32 x (18-8-10) 

15 x 5 x 3 x(32 x     0        )

15 x 5 x 3        0          = 0

             h nha

15 x 5 x 3 x ( 18 x 32 -  8 x 32 - 10 x 32 )

= 15 x 5 x 3 x  ( 0 x 32 )

= 15 x 5 x 3 x     0

=         0

\(\dfrac{4}{3.5}+\dfrac{8}{5.9}+\dfrac{12}{9.15}+...+\dfrac{32}{x\left(x+16\right)}=\dfrac{16}{15}\)

\(2.\left(\dfrac{2}{3.5}+\dfrac{4}{5.9}+\dfrac{6}{9.15}+..+\dfrac{16}{X.\left(X+16\right)}\right)=\dfrac{16}{15}\)

\(\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{15}+...+\dfrac{1}{X}-\dfrac{1}{X+16}=\dfrac{8}{15}\)

\(\dfrac{1}{X+16}=\dfrac{1}{3}-\dfrac{8}{15}\)

\(\dfrac{1}{X+16}=\dfrac{-1}{5}\)

\(X+16=-5\)

\(X=-21\)

a) \(125\times25\times8\times4\)
\(\Rightarrow\left(125\times8\right)\times\left(25\times4\right)\)
\(\Rightarrow1000\times100\)
\(\Rightarrow100000\)

\(\text{a. 125 x 25 x 8 x 4 }\\ =125.8.25.4\\ =1000.100=100000\)

\(\text{ b. 25 x 32 x 125 x 15}\\ =25.15.32.125\\ =375.4000=1500000\)

b.25 x 32 x 125 x 15=25 x 4 x 8 x 125 x 15

                                =(25 x 4) x (125 x 8) x15

                                =100 x 1000 x 15 = 1500000

bn này bị j rùi mọi người!đây mà là toán lớp 3!

\(x=\left(\frac{33}{5}:6-0,125\cdot8+\frac{32}{15}\cdot0,03\right)\cdot\frac{11}{4}\)

\(x=\left(\frac{33}{5}\cdot\frac{1}{6}-\frac{1}{8}\cdot8+\frac{32}{15}\cdot\frac{3}{100}\right)\cdot\frac{11}{4}\)

\(x=\left(\frac{11}{10}-1+\frac{8}{125}\right)\cdot\frac{11}{4}\)

\(x=\frac{41}{250}\cdot\frac{11}{4}\)

\(x=\frac{451}{100}\)

\(x=\left(\frac{33}{5}:6-0,125.8+\frac{32}{15}.0,03\right).\frac{11}{4}\)

\(< =>x=\left(\frac{33}{30}-1+\frac{32}{15}.\frac{3}{100}\right).\frac{11}{4}\)

\(< =>x=\left(\frac{3}{30}+\frac{32}{500}\right).\frac{11}{4}\)

\(< =>x=\left(\frac{1}{10}+\frac{8}{125}\right).\frac{11}{4}\)

\(< =>x=\frac{41}{250}.\frac{11}{4}=\frac{451}{100}\)

x=(11/10-2+8/125)×11/4

x=(-9/10+8/125)×11/4

x=-209/250×11/4

x=-2299/1000

\(\frac{1}{4}.\frac{2}{6}.\frac{3}{8}....\frac{15}{32}=\frac{1}{2}.\frac{1}{2}.\frac{1}{2}.\frac{2}{3}.\frac{1}{2}.\frac{3}{4}....\frac{1}{2}.\frac{15}{16}\)

\(=\left(\frac{1}{2}.\frac{1}{2}.....\frac{1}{2}\right).\left(\frac{1}{2}.\frac{2}{3}.\frac{3}{4}....\frac{15}{16}\right)\)

Số số \(\frac{1}{2}\)là (15-1):1+1=15 số

Do đó \(\left(\frac{1}{2}.\frac{1}{2}.....\frac{1}{2}\right).\left(\frac{1}{2}.\frac{2}{3}.\frac{3}{4}....\frac{15}{16}\right)=\left(\frac{1}{2}\right)^{15}.\frac{1.2.3....15}{2.3.4....15.16}\)

\(=\frac{1}{2^{15}}.\frac{1}{16}=\frac{1}{2^{15}}.\frac{1}{2^4}=\frac{1}{2^{15+4}}=\frac{1}{2^{19}}\)

\(\Rightarrow2^x=\frac{1}{2^{19}}\)

\(\Rightarrow x=-19\)