Chapter 8 - Systems of Linear Equations and Problem Solving - 8.2 Solving by Substitution or Elimination - 8.2 Exercise Set - Page 517: 66

$$.00061$$

Recall, for a number to be in scientific notation, it must be in the form $a\times 10^b$, where a must be between 1 and 10. Thus, we simplify the expression. If necessary, we change b until the value of a is between 1 and 10. Doing this, we find that the expression becomes: $$6.1\times10^{-4} \rightarrow .00061$$