Formulas are mathematical laws that help us solve problems.
Decimals are a type of number; graphs are displays of data; percentages are comparisons of a number to 100; and fractions are a type of number.
A linear equation will contain a term in x has the highest degree. For example y = 2x - 5 . A non linear will contain terms with exponents 2 or higher
eg x^2 - 2x - 5 is nonlinear.