$\iff -\frac{23}{5}\cdot \frac{50}{23}<=x<=-\frac{13}{5}\cdot \frac{7}{5}$

=>-10<=x<=-91/25

hay $x\in \left\{-10;-9;-8;-7;-6;-5;-4\right\}$

4405

4045

cuốn sách dư số trang là:

90-19=71(trang)

Đ/S:.......................................

22

a: A=210⋅38−22⋅227⋅3205⋅210⋅212⋅312−7⋅229⋅318A=210⋅38−22⋅227⋅3205⋅210⋅212⋅312−7⋅229⋅318

=210⋅38−229⋅3205⋅222⋅312−7⋅229⋅318=210⋅38−229⋅3205⋅222⋅312−7⋅229⋅318

=210⋅38(1−219⋅312)222⋅312(5−7⋅27⋅36)=1212⋅134⋅1−219⋅3125−7⋅27⋅36

B=210⋅13⋅(1+5)28⋅104=22⋅13104⋅6B=210⋅13⋅(1+5)28⋅104=22⋅13104⋅6

=52104⋅6=6⋅12=3=52104⋅6=6⋅12=3

C=210⋅38−2⋅34⋅24210⋅38+28⋅38⋅22⋅5C=210⋅38−2⋅34⋅24210⋅38+28⋅38⋅22⋅5

=25⋅34(25⋅34−1)210⋅38⋅6=125⋅134⋅25916

lx