=15(21/43+33/35)

=6462/301

\(=15.\left(\frac{21.10101}{43.10101}+\frac{33.10101}{35.10101}\right)\)

\(=15.\left(\frac{21}{43}+\frac{33}{35}\right)\)

\(=15.\frac{2154}{1505}\)

\(=\frac{6462}{301}\)

15 x (\(\frac{212121}{434343}+\frac{333333}{3535335}\)) = 15 x ( \(\frac{21.10101}{43.10101}+\frac{33.10101}{35.10101}\))

= 15 x ( \(\frac{21}{43}+\frac{33}{35}\)) = 5 x 3 x \(\frac{735}{1505}+\frac{1419}{1505}\)= 5 x 3 x \(\frac{2154}{1505}\)= \(\frac{6462}{301}\)

a)=15.2154/1505

=6462/301

b)=461179719/138076

c,=134724+400/135136-12

=135124/135124

=1

\(a)15.\left(\dfrac{212121}{434343}+\dfrac{333333}{353535}\right)\)

\(=15.\left(\dfrac{21}{43}+\dfrac{33}{35}\right)\)

\(=15.\dfrac{2154}{1505}\)

\(=\dfrac{6462}{301}\)

a) \(15\times\left(\frac{212121}{434343}+\frac{333333}{353535}\right)=15\times\left(\frac{21\times10101}{43\times10101}+\frac{33\times10101}{35\times10101}\right)\)

\(=15\times\left(\frac{21}{43}+\frac{33}{35}\right)=\frac{6462}{301}\)

b) \(\frac{639\times721721}{721\times639639}=\frac{639\times721\times1001}{721\times639\times1001}=1\)

c) \(\frac{327\times412+400}{328\times412-12}=\frac{\left(328-1\right)\times412+400}{328\times412-12}=\frac{328\times412-412+400}{328\times412-12}\)

\(=\frac{328\times412-12}{328\times412-12}=1\)

d) \(9\times\left(\frac{151515}{171717}+\frac{131313}{181818}\right)=9\times\left(\frac{15\times10101}{17\times10101}+\frac{13\times10101}{18\times10101}\right)=9\times\left(\frac{15}{17}+\frac{13}{18}\right)\)

\(=9\times\frac{491}{306}=\frac{491}{34}\)

thank bn

=15x(21/43+33/35)

=tự tính

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