Đáp án + Giải thích các bước giải:
a)
`1001^2=(1000+1)^2=1000^2+2.1000.1+1^2=1000000+2000+1=1002001`
b)
`29,9.30,1=(30-0,1)(30+0,1)=30^2-(0,1)^2=900-0,01=899,99`
c)
`199^2=(200-1)^2=200^2-2.200.1+1^2=40000-400+1=39601`
d)
`84^2-16^2=(84-16)(84+16)=68.100=6800`
e)
`313^2-312^2=(313-312)(313+312)=1.625=625`
f)
`47.53=(50-3)(50+3)=50^2-3^2=2500-9=2491`