用简便方法运算10²-9²+8²-7²+6²-5²+4²-3²+2²-1²和1.4²+2.8×1.6+1.6²
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/11 14:21:22
![用简便方法运算10²-9²+8²-7²+6²-5²+4²-3²+2²-1²和1.4²+2.8×1.6+1.6²](/uploads/image/z/245279-47-9.jpg?t=%E7%94%A8%E7%AE%80%E4%BE%BF%E6%96%B9%E6%B3%95%E8%BF%90%E7%AE%9710%26%23178%3B-9%26%23178%3B%2B8%26%23178%3B-7%26%23178%3B%2B6%26%23178%3B-5%26%23178%3B%2B4%26%23178%3B-3%26%23178%3B%2B2%26%23178%3B-1%26%23178%3B%E5%92%8C1.4%26%23178%3B%2B2.8%C3%971.6%2B1.6%26%23178%3B)
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用简便方法运算10²-9²+8²-7²+6²-5²+4²-3²+2²-1²和1.4²+2.8×1.6+1.6²
用简便方法运算10²-9²+8²-7²+6²-5²+4²-3²+2²-1²
和1.4²+2.8×1.6+1.6²
用简便方法运算10²-9²+8²-7²+6²-5²+4²-3²+2²-1²和1.4²+2.8×1.6+1.6²
10²-9²+8²-7²+6²-5²+4²-3²+2²-1²
=(10+9)(10-9)+(8+7)(8-7)+(6+5)(6-5)+(4+3)(4-3)+(2+1)(2-1)
=19+15+11+7+3
=55
.
1.4²+2.8×1.6+1.6²
=1.4²+2×1.4×1.6+1.6²
=(1.4+1.6)²
=3²
=9