I'm not sure what coefficients mean I tried looking it up but the description for it was very confusing to me.
Coefficient is a number used to multiply a variable. for example 6z means 6 times z, and "z" is a variable, so 6 is a coefficient. Variables with no number have a coefficient of 1. Suppose if you see only x, it's actually 1x. Sometimes a letter stands in for the number. For example: In ax2 + bx + c, "x" is a variable, and "a" and "b" are coefficients.
In the expression 3x-4y+2, we see three terms 3x, -4y, 2
Terms are composed of coefficient and a variable
In 3x, 3 is the coefficient and x is the variable
In -4y, -4 is the coefficent and y is the variable
In 2, there's no variable, so it is a special term called a constant.
Coefficient can be whole number, positive or negative, fraction, decimal etc.