To simplify the expression, we can first rewrite the terms using exponent rules:
[tex]8 {}^{ \frac{2}{3} } = 8^{ \frac{2}{3} } = (2^3)^{ \frac{2}{3} } = 2^{3 \cdot \frac{2}{3} } = 2^2 = 4[/tex]
Next, we have:
[tex]\sqrt[3]{(-8)^{-2}} = (-8)^{- \frac{2}{3} } = \left( \frac{1}{-8^{2}} \right)^{ \frac{1}{3} } = \left( \frac{1}{64} \right)^{ \frac{1}{3} } = (\frac{1}{4})[/tex]
Substitute these values back into the original expression:
[tex]4 \times a - \frac{1}{4} = 4a - \frac{1}{4}[/tex]
Therefore, the simplified expression is [tex]4a - \frac{1}{4}[/tex].
To simplify the expression, we can first rewrite the terms using exponent rules:
[tex]8 {}^{ \frac{2}{3} } = 8^{ \frac{2}{3} } = (2^3)^{ \frac{2}{3} } = 2^{3 \cdot \frac{2}{3} } = 2^2 = 4[/tex]
Next, we have:
[tex]\sqrt[3]{(-8)^{-2}} = (-8)^{- \frac{2}{3} } = \left( \frac{1}{-8^{2}} \right)^{ \frac{1}{3} } = \left( \frac{1}{64} \right)^{ \frac{1}{3} } = (\frac{1}{4})[/tex]
Substitute these values back into the original expression:
[tex]4 \times a - \frac{1}{4} = 4a - \frac{1}{4}[/tex]
Therefore, the simplified expression is [tex]4a - \frac{1}{4}[/tex].