Fractional Exponents Revisited Common Core Algebra Ii Today

Eli frowns. “So the denominator is the root, the numerator is the power. But order doesn’t matter, right?”

“But what about ( 27^{-2/3} )?” Eli asks, pointing to his worksheet.

Eli writes: ( \left(\frac{1}{4}\right)^{-1.5} = 8 ). He stares. “That’s beautiful.” Fractional Exponents Revisited Common Core Algebra Ii

“Rewrite ( 1.5 ) as ( \frac{3}{2} ).” Ms. Vega leans in. “The rule holds for all rational exponents. Now: The base is ( \frac{1}{4} ). Negative exponent → flip it: ( 4^{3/2} ). Denominator 2 → square root of 4 is 2. Numerator 3 → cube 2 to get 8. Done.”

“I get ( x^{1/2} ) is square root,” Eli sighs, “but ( 16^{3/2} )? Do I square first, then cube root? Or cube root, then square?” Eli frowns

“( 27^{-2/3} ) whispers: ‘I was once ( 27^{2/3} ), but someone took my reciprocal.’ So first, undo the mirror: ( 27^{-2/3} = \frac{1}{27^{2/3}} ). Then apply the fraction rule: cube root of 27 is 3, square is 9. So answer: ( \frac{1}{9} ).”

The Fractal Key

Eli’s pencil moves: ( 27^{-2/3} = \frac{1}{(\sqrt[3]{27})^2} = \frac{1}{3^2} = \frac{1}{9} ). “It works.”