1.   528,558,588

2.   345 

190-90=100

190-90=100

190-90=100

190-90=100

k nhé

1+2+3+4+5+6+7+8-9

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

=(1+5+10+10+10)-9

=36-9

=27

mình ne

cho xin 1 k nha

Ta có:\(\frac{x}{100}=\frac{25}{x}\Rightarrow x^2=2500\)

\(\Leftrightarrow\orbr{\begin{cases}x=50\\x=-50\end{cases}}\)