(8 x 7 - 16 - 5 x 8) x (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9)

= [8 x 7 - 8 x 2 - 5 x 8] x [(1 + 9) + (2 + 8 ) + (3 + 7) + (4 + 6) + 5]

= [8 x (7 - 2 - 5)] x [10 + 10 + 10 + 10 + 10 + 5]

= (8 x 0) x 45

= 0

1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19

= (1 + 9) + (3 + 7) + (5 + 15) + (11 + 19) + (13 + 17)

= 10 + 10 + 20 + 30 + 30

= 100

a)1+2+3+4+5+6+7+8+9

=(1+9)+(2+8)+(3+7)+(4+6)+5

=10+10+10+10+5

=10x4+5=45

b)8x3+8x7

=8x(3+7)

=8x10=80

c)8x172-8x72

=8x(172-72)

=8x100=800

a. 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 +9

= (1 + 9) + (2 + 8) + (3 + 7) + ( 4 + 6) + 5

= 10 + 10 + 10 + 10 + 5

= 45

=(8*7-8*2-8*5)*((1+9)+(2+8)+(3+7)+(4+6)+5)

=(8*(7-2-5))*(10+10+10+10+5)

=(8*0)*(10+10+10+10+5)

=0*(10+10+10+10+5)

=0

0 ko ns nhiều

thì sao bn bảo tui sai

a: \(\dfrac{4^5\cdot9^4-2\cdot6^9}{2^{10}\cdot3^8+6^8\cdot20}\)

\(=\dfrac{2^{10}\cdot3^8-2\cdot2^9\cdot3^9}{2^{10}\cdot3^8+2^8\cdot3^8\cdot2^2\cdot5}\)

\(=\dfrac{2^{10}\cdot3^8-2^{10}\cdot3^9}{2^{10}\cdot3^8+2^{10}\cdot3^8\cdot5}\)

\(=\dfrac{2^{10}\cdot3^8\left(1-3\right)}{2^{10}\cdot3^8\left(1+5\right)}=\dfrac{-2}{6}=-\dfrac{1}{3}\)

h

Các bạn giúp mk nhé mk đang cần gấp ^_^

\(\frac{-5}{8}.\frac{5}{12}+\frac{-5}{8}.\frac{7}{12}+\frac{17}{8}\)

= \(\frac{-5}{8}.\left(\frac{5}{12}+\frac{7}{12}\right)+\frac{17}{8}\)

= \(\frac{-5}{8}.\frac{12}{12}+\frac{17}{8}\)

-1/3