Question
Evaluate: $2^5 \times 15^0+(-3)^3-\left(\frac{2}{7}\right)^{-2}$
✓
Answer
$\begin{aligned} & 2^5 \times 15^0+(-3)^3-\left(\frac{2}{7}\right)^{-2} \\ & =2 \times 2 \times 2 \times 2 \times 2 \times 1+(-3) \times(-3) \times(-3)-\left(\frac{7}{2}\right) \times\left(\frac{7}{2}\right) \\ & =32 \times 1-27-\frac{49}{4}\left(\because a^0=1\right) \\ & =\frac{32 \times 4}{1 \times 4}-\frac{27 \times 4}{1 \times 4}-\frac{49}{4 \times 1}(\because \text { LCM }=4) \\ & =(128-108-49) / 4=-\frac{29}{4}=-7 \frac{1}{4}\end{aligned}$
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