Rewrite the expression using only positive exponents, and simplify. Assume that any variables in the expression are nonzero. $\frac { s ^ { - 1 } + r ^ { - 1 } } { s ^ { - 1 } - r ^ { - 1 } }$
A) $\frac { r - s } { r + s }$
B) $s ^ { 2 } + r ^ { 2 }$
C) $\frac { r + s } { r - s }$
D) $\frac { s + r } { s - r }$
E) $\frac { s - r } { s + r }$

Question

Quizplus · Accepted Answer

To make the exponents positive, we can flip both the numerator and denominator to get $\frac{1/s+1/r}{1/s-1/r}=\frac{r+s}{r-s}$. This is equivalent to choice C.

Rewrite the Expression Using Only Positive Exponents, and Simplify s−1+r−1s−1−r−1\frac { s ^ { - 1 } + r ^ { - 1 } } { s ^ { - 1 } - r ^ { - 1 } }s−1−r−1s−1+r−1​

Rewrite the Expression Using Only Positive Exponents, and Simplify $\frac { s ^ { - 1 } + r ^ { - 1 } } { s ^ { - 1 } - r ^ { - 1 } }$