Chapter 7.1, Problem 42PPE

To determine

To Evaluate: The expression $r^0{s}^{-2}$ for $r=-3$ and $s=5$

Answer to Problem 42PPE

The required solution is $9$

Explanation of Solution

Given information:

  $r^0{s}^{-2}$

  $r=-3$ and $s=5$

Concept Used:

Negative Exponent:

  $a^{-n}=\frac{1}{a^n}$

Where a is a non-zero number and n is an integer.

Zero as an Exponent:

  $a^0=1$

Where a is a non-zero number.

Calculation:

  $r^0{s}^{-2}$

Applying Negative Exponent concept

  $=\frac{r^0}{s^2}$

Applying Zero as an Exponentconcept

  $=\frac{1}{s^2}$

Substituting the known value:

  $\begin{array}{l}=\frac{1}{5^2}\\ =\frac{1}{25}\end{array}$