Answer
[68,86]
Work Step by Step
The formula provided in example 9: C=$\frac{5}{9}$(F-32)
1. Substitute the formula into the given range:
20$\leq$$\frac{5}{9}$(F-32)$\leq$30
2. Distribute:
20$\leq$$\frac{5}{9}$F-$\frac{160}{9}$$\leq$30
3. Add $\frac{160}{9}$ to each section of the inequality.
$\frac{340}{9}$$\leq$$\frac{5}{9}$F$\leq$$\frac{430}{9}$
4. Divide each section by $\frac{5}{9}$, which is the same as multiplying by $\frac{9}{5}$
$\frac{3060}{45}$$\leq$F$\leq$$\frac{3870}{9}$
5. Simplify
68$\leq$F$\leq$86
The solution interval is greater than or equal to 68, and less than or equal to 86. Use [] to denote that it's 'or equal to'.
