问题
填空题
已知x,y为正整数,且x2-y2=53,则x3-y3-2(x+y)+10的值是______.
答案
∵53是质数,
∴x2-y2=(x+y)(x-y)=53×1,
∴
,∴x+y=53 x-y=1
,x=27 y=26
原式=(x-y)(x2+xy+y2)-2(x+y)+10
=(x-y)2+3xy-106+10=1+3×702-96=2011.
故答案为2011.
已知x,y为正整数,且x2-y2=53,则x3-y3-2(x+y)+10的值是______.
∵53是质数,
∴x2-y2=(x+y)(x-y)=53×1,
∴
,∴x+y=53 x-y=1
,x=27 y=26
原式=(x-y)(x2+xy+y2)-2(x+y)+10
=(x-y)2+3xy-106+10=1+3×702-96=2011.
故答案为2011.