I think the domain and range are infinite
<span>When your income is more than your expenses, y</span>ou have surplus
Answer:

Variable is a symbol that represents a quantity in a mathematical expression, as used in many sciences. Variable (research), a logical set of attributes. Variable star, a type of astronomical star.

A constant, sometimes also called a "mathematical constant," is any well-defined real number which is significantly interesting in some way. A function, equation, etc., is said to "be constant" (or be a constant function) if it always assumes the same value independent of how its parameters are varied.
4 because the triangles equals half and a square equals a full
Complementary angels add up to 90°
so x+18°=90°
so x=90-18=72°