Exercise 39 Page 422

To evaluate the given expression for r = -3 and s = 5, we should substitute these values into the expression and simplify as much as possible.

3r/s^(-2)

SubstituteII

r= -3, s= 5

3( -3)/5^(-2)

MultPosNeg

a(- b)=- a * b

-9/5^(-2)

NegExponentToFrac

a^(- m)=1/a^m

-9/1/5^2

DivByFracD

a/b/c= a * c/b

-9 * 5^2/1

DivByOne

a/1=a

-9 * 5^2

CalcPow

Calculate power

-9 * 25

MultNegPos

(- a)b = - ab

-225