tính hợp lí :
a) (10^2+11^2+12^2):(13^2+14^2)
b)1.2.3...2013 - 1.2.3...2012 - 1.2.3...2012^2
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b/1.2.3.....2013 - 1.2.3....2012-1.2.3...20122
= (1.2.3...2012.2013-1.2.3...2012)-1.2.3...2012.2012
= 1.2.3...2012(2013-1-2012)
=1.2.3...2012.0=0
1.2.3...2013-1.2.3...2012-1.2.3...20122= (1.2.3...2013-1.2.3...2012) - 1.2.3...20122 = [1.2.3...2012(2013-1)] - 1.2.3...20122 = 1.2.3...2012.2012 - 1.2.3...20122 = 1.2.3...20122 - 1.2.3...20122 = 0
1 . 2 . 3 . ...... 2012 . ( 2013 - 1 - 2012 )
1 . 2 . 3 ..........2012 . ( 0 ) = 0
a,(10^2+11^2+12^2):(13^2+14^2)
=(100+121+144);(169+196)
=365:365
=1
b,1.2.3...9-1.2.3...8-1.2.3...8^2=0
a)=(100+121+144):(169+196)=365:365=1
b)=1.2.3...8.(9-1-8)=1.2.3...8.0=0
k mk nhaa
\(b)\) \(1.2.3...9-1.2.3...8-1.2.3...8^2\)
\(=\)\(1.2.3...8\left(9-1-8\right)\)
\(=\)\(1.2.3...8\left(9-9\right)\)
\(=\)\(1.2.3...8.0\)
\(=\)\(0\)
mk làm đk câu b thui àk : (câu b dễ lắm)
b, 1.2.3...2013-1.2.3...2012-1.2.3...20122
=1.2.3...2012(2013-1-2012)
=1.2.3...2012.0
=0
k giùm mk đi m.n ơi
#quý_lắm_ạ