ban j minh 200cm3=...cc nha

\(220,33-\overline{ab,cd}=\overline{abc,d}\)

\(\left(220,33-\overline{ab,cd}\right)\times100=abc\times100\)

\(22033-\overline{abcd}=\overline{abcd}\times10\)

\(22033=\overline{abcd}\times10+\overline{abcd}\)

\(22033=\overline{abcd}\times11\)

\(\overline{abcd=}22033\div11=2003\)

Xxxxx

Ô ni te

90a,bc : a,bc = 721 

(900 + a,bc) : a,bc = 721

900 : a,bc + a,bc  : a,bc = 721

900 : a,bc + 1 = 721

900 : a,bc = 721 - 1 = 720

a,bc = 900 : 720 = 1,25

Vậy a = 1; b = 2; c = 5

=> (900 + a,bc . 0,01) : (a,bc . 0,01) = 721

=> 900 :  (a,bc . 0,01) + (a,bc . 0.01) :  (a,bc . 0,01) = 721

=> 900 : (a,bc . 0,01) + 1 = 721

=> 900 :  (a,bc . 0,01) = 720

=> a,bc . 0,01 = 1,25

=> abc = 125

Vậy a = 1 ; b = 2 và c = 5

\(\frac{a^2+3ab}{a^2-9b^2}+\frac{2a^2-5ab-3b^2}{6ab-a^2-9b^2}\)

\(=\frac{a\left(a+3b\right)}{\left(a-3b\right)\left(a+3b\right)}+\frac{2a^2-6ab+ab-3b^2}{-\left(a^2-6ab+9b^2\right)}\)

\(=\frac{a}{a-3b}+\frac{\left(a-3b\right)\left(2a+b\right)}{-\left(a-3b\right)^2}=\frac{a}{a-3b}-\frac{2a+b}{a-3b}=\frac{a-2a-b}{a-3b}=\frac{-a-b}{a-3b}\) =\(\frac{a+b}{3b-a}\)

\(\frac{a^2+an+bn+ab}{3bn-a^2-an+3ab}\)

\(=\frac{a\left(a+n\right)+b\left(a+n\right)}{3b\left(n+a\right)-a\left(a+n\right)}=\frac{\left(a+b\right)\left(a+n\right)}{\left(3b-a\right)\left(n+a\right)}=\frac{a+b}{3b-a}\)

Do đó: \(\frac{a^2+3ab}{a^2-9b^2}+\frac{2a^2-5ab-3b^2}{6ab-a^2-9b^2}=\frac{a^2+an+bn+ab}{3bn-a^2-an+3ab}\)

Ta xét số B, có:
1ab9 = 1009 + ab0
9ac = 900 + ac
9b = 90 + b
Vậy B = 1009 + ab0 + 900 + ac + 90 + b = 1009 + 900 + 90 + ab0 + a0 + c + b = 1999 + ab0 + a0 + c + b = 1999 + abc + ab > 1997 + abc + ab.
Vậy B > A