( - 15 ) . 25 + 15 . 16 + ( - 9 ) . 85

= 15 . ( - 25 ) + 15 . 16 + ( - 9 ) . 85

= 15 [ ( - 25 ) + 16 ] + ( - 9 ) . 85

= 15  . ( - 9 ) + ( - 9 ) . 85

= ( - 9 ) ( 15 + 85 )

= ( - 9 ) . 100

= - 900

Hok tốt

a)

b)

c)

d)

\(\frac{9^{14}.25^5.8^7}{8^{12}.615^3.25^3}\)

\(=\frac{\left(3^3\right)^{14}.\left(5^2\right)^5.8^7}{8^{12}.\left(3.5.41\right)^3.\left(5^2\right)^3}\)

\(=\frac{3^{42}.5^{10}.8^7}{8^{12}.3^3.5^7.41^3}\)

\(=\frac{3^{39}.5^3}{8^5.41^3}\)

ai biết ko ?

a=25x(725+250+25)

  =25x1000

  =25000

cái b tôi ko biết'

a) \(\frac{15}{9}:\frac{3}{4}:\frac{7}{5}=\frac{15}{9}.\frac{4}{3}.\frac{5}{7}=\frac{300}{189}=\frac{100}{63}\)

b ) \(\frac{23}{7}.\frac{25}{2}-\frac{23}{7}.\left(5+\frac{1}{2}\right)=\frac{23}{7}.\left(\frac{25}{2}-\frac{11}{2}\right)=\frac{23}{7}.7=23\)

a)\(\frac{100}{63}\)

b)   23

a)\(\frac{15}{9}x\frac{4}{3}x\frac{5}{7}=\frac{15x4x5}{9x3x7}=\frac{100}{63}\)

b)23

bn gg ko đồng hành cùng bn à

a/ x= 9/20

b/ x= 52

A = 78 x 31 + 78 x 24 + 78 x 17 + 22 x 72

A = 78 x ( 31 + 24 + 17 ) + 22 x 72

A = 78 x 72 + 22 x 72

A = 72 x ( 78 + 22 ) 

A = 72 x 100

A = 7200

C = 53 x 39 + 47 x 39 - 53 x 21 - 47 x 21

C = 39 x ( 53 + 47 ) - 21 x ( 53 - 47 )

C = 39 x 100 - 21 x 6

C = 3900 - 126

C = 3774

ko pc tui thua bn 1 lp 

A = 78 x 31 + 78 x 24 + 78 x 17 + 22 x 72

A = 78 x ( 31 + 24 +17 ) + 22 x 72

A = 78 x 72 + 22 x 72

A = 72 x ( 78 + 22 )

A = 72 x 100

A = 7200