如题所述
=(4²-1)+(6²-1)+(8²-1)+……+(50²-1)
=(4²+6²+8²+……+50²)-(1+1+1+……+1)
=(4×2²+4×3²+4×4²+……+4×25²)-24
=4×(2²+3²+4²+……+25²)-24
=4×(25×26×51÷6-1²)-24
=22096-24
=22072
=(4²+6²+8²+……+50²)-(1+1+1+……+1)
=(4×2²+4×3²+4×4²+……+4×25²)-24
=4×(2²+3²+4²+……+25²)-24
=4×(25×26×51÷6-1²)-24
=22096-24
=22072
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