问题213: 1 5/7×(1/4+1/2÷4/5)
$1 \frac{5}{7} \times\left(\frac{1}{4}+\frac{1}{2} \div \frac{4}{5}\right)$
$$ \begin{aligned} & 1 \frac{5}{7} \times\left(\frac{1}{4}+\frac{1}{2} \div \frac{4}{5}\right) \\ = & \frac{12}{7} \times\left(\frac{1}{4}+\frac{1}{2} \times \frac{5}{4}\right) \\ = & \frac{12}{7} \times \frac{1}{4}+\frac{12}{7} \times \frac{1}{2} \times \frac{5}{4} \\ = & \frac{3}{7}+\frac{15}{14} \\ = & \frac{21}{14} \\ = & \frac{3}{2} \end{aligned} $$
添加微信可以更快获取解答(请注明有偿答疑)
最后修改于3月19日
前一篇:问题212: 求函数f(x)=12 x^5+15 x^4-40 x^3的定义域和极值
下一篇:问题214: lim(5x^2/1−x^2+2^1/x)