“微信扫一扫”进入题库练习及模拟考试

初中数学七年级上册(581题)


已知\(a\)\(b\)互为相反数,\(c\)\(d\)互为倒数,\(x\)的绝对值是2,试求:\({x^2} - {(a + b)^{2021}} + {( - cd)^{2022}}\)



知识点:第一章 有理数


参考答案:解:由已知可得\(a + b = 0\),\(cd = 1\),\(x = \pm 2\).

当\(x = 2\)时,原式\( = {2^2} - (0 + 1) \times 2 + {0^{2007}} + {( - 1)^{2008}} = 4 - 2 + 1 = 3\);


当\(x = - 2\)时,原式\( = {( - 2)^2} - (0 + 1) \times ( - 2) + {0^{2007}} + {( - 1)^{2008}} = 4 + 2 + 1 = 7\).

进入考试题库