Equations and Inequalities Practice Test

A dentist mixes $x$ mL of fluoride concentrate at $\$0.40$/mL plus $$5$ bottle cost; if total is $\$21$, solve $0.40x+5=21$ for $x$.

A hygiene kit costs $\$25$ plus $$3$ per disposable item; if total is $\$55$, solve $25+3x=55$ for $x$.