Question

Va rog ajutați-mă !!!!

Answer 1

81^2=(80+1)^2=80^2+2×80+1=6400+160+1=6561
49^2=(50-1)^2=50^2-2×50+1=2500-100+1=2401
(100-1)^2=10000-200+1=9801
72^2=(70+2)^2=4900+2×2×70+4=
4900+280+4=5184
(100+2)^2=10000+400+4=10404
88^2=(90-2)^2=8100-360+4


79×81=(80-1)(80+1)=6400-1=6399
59×61=(60-1)(60+1)=3600-1=3599
98×102=(100-2)(100+2)=10000-4=9996
198×202=(200-2)(200+2)=40000-4=
39996