规律(10a+5)^2-25=a*(a+1)*100 a=1,2,3……
解答:左边=(10a+5)^2-25=100a^2+100a+25-25=100a^2+100a=100*a*(a+1)=右边
(10a+5)^2-25=100a*(a+1)
证明
(10a+5)^2-25
=(100a^2+100a+25)-25
=100a^2+100a
=100a(a+1)
(10a+5)^2-25=100*a*(a+1)
证明
(10a+5)^2-25=(100a^2+100a+25)-25=100a^2+100a=100a(a+1)