解:因?yàn)殚L(zhǎng)方形紙板的長(zhǎng)為?$10\ \mathrm {cm},$?寬為?$6\ \mathrm {cm},$?四角割去邊長(zhǎng)為?$x\mathrm {cm} $?的
小正方形,所以折疊后形成的無蓋長(zhǎng)方體的長(zhǎng)為?$(10 - 2x)\mathrm {cm},$?
寬為?$(6 - 2x)\mathrm {cm},$?高為?$x\mathrm {cm}$?
可得該長(zhǎng)方體的體積為?$V=(10 - 2x)(6 - 2x)x (\mathrm {cm}^3)$?