Answer:
In algebra, an equation is a mathematical expression that contains an equals sign. ... An inequality is a mathematical expression that contains inequality signs. For example, y≤ 12x is an inequality. Inequalities are used to tell us that an expression is either larger or smaller than another expression.
Step-by-step explanation:
Answer:
S= -3
Step-by-step explanation:
3s-12=-21
3s= -21+12
3s= -9
s= -9/3
s= -3