ข้อสอบคณิต O-NET - 2560

$$\begin{gathered} \mathrm{จากโจทย์} \\ \frac{a^{-{\displaystyle \frac{1}{2}}}·a^{{\displaystyle \frac{3}{2}}}+{16}^{-{\displaystyle \frac{1}{2}}}·{27}^{{\displaystyle \frac{1}{3}}}}{5{\left({\displaystyle \frac{1}{2}}\right)}^{-3}+2{\left({\displaystyle \frac{1}{2}}\right)}^0} = \frac{1}{2} \\ \frac{a^{-{\displaystyle \frac{1}{2}+\frac{3}{2}}}+{\displaystyle \frac{1}{\sqrt{16}}}·\sqrt[3]{27}}{5{\left(2\right)}^3+2\left(1\right)} = \frac{1}{2} \end{gathered}$$

$$\begin{gathered} \frac{a^{{\displaystyle \frac{\cancel{2}}{\cancel{2}}}}+{\displaystyle \frac{3}{4}}}{42} = \frac{1}{2} \\ a+\frac{3}{4} = 21 \\ a = 21-\frac{3}{4} \\ = \frac{81}{4} \\ \mathrm{ดังนั้น} \mathrm{ตอบข้อ} 2 \end{gathered}$$