Exercise 4 Page 461

To rationalize a monomial denominator, we multiply the numerator and denominator by a radical that will eliminate the radical in the denominator. Because the denominator is a square root, we need to multiply it by a square root that will give us a perfect square under the radical.

\frac{2}{7}

ExpandFrac

$\frac{a}{b} = \frac{a \cdot 7}{b \cdot 7}$

\frac{2 7}{7 \cdot 7}

ProdSqrt

$a \cdot b = a \cdot b$

\frac{2 7}{7 \cdot 7}

ProdToPowTwoFac

$a \cdot a = a^{2}$

\frac{2 7}{7 ^{2}}

SqrtPowToNumber

$a^{2} = a$

\frac{2 7}{7}