\(=\dfrac{2^{80}\left(1+2+2^2\right)}{2^{78}\left(1+2+2^2\right)}=2^2=4\)

a)\(69^2-31^2=\left(69-31\right)\left(69+31\right)=38.100=3800\)

\(1023^2-23^2=\left(1023-23\right)\left(1023+23\right)=1000.1046=1046000\)

295-(31-2^2.5^2)

295-(31-4.25)

295-(31.100)

295-3100

-2805

295 - (31 - 2² x 5²)

= 295 - (31 - 4 x 25)

= 295 - (31 - 100)

= 295 - (-69)

= 295 + 69

= 364

Học tốt!!!

a=897

b=8668

c=7

d=3671

a,=29.(69+31)-2300

=29.100-2300

=2900-2300

=600

MK NÓI THẬT MẤY BÀI NÀY DỄ ỢT

\(C=\frac{5^2}{1.6}+\frac{5^2}{6.11}+...+\frac{5^2}{26.31}\)

\(=5.\left(\frac{5}{1.6}+\frac{5}{6.11}+...+\frac{5}{26.31}\right)\)

\(=5.\left(1-\frac{1}{6}+\frac{1}{6}-\frac{1}{11}+...+\frac{1}{26}-\frac{1}{31}\right)\)

\(=5.\left(1-\frac{1}{31}\right)\)

\(=5.\frac{29}{31}\)

\(=\frac{145}{31}\)

sai rồi bạn ạ , phải ra 150/31 mới đúng !

a)-84:4+3^9:3^7+5^0

=-21+(3^9:3^7)+1

=-21+3^2+1

=-21+9+1

=-12+1

=-11

b)295-(31-2^5.5)^2

=295-(31-32.5)^2

=295-(-129)^2

=295+129^2

=295-16641

=-16346

tick cho mk nha bạn

a) -84 : 4 + 3^ 9 : 3 ^ 7 + 5 ^0

=-84:4+3^2+1

=-84:4+9+1

=-21+9+1

=-12+1

=-11

b) 295 - ( 31 - 2^ 5. 5) ^2

= 295 - ( 31 -32. 5)^2

= 295 - (-129)^2

=295-16641

=-16346