The coefficient of any variable is the number that is written next to it, and is not separated by any sign from the variable, except the multiplication sign.

For example, the coefficient of 'b' in 4b is 4.

Again, the coefficient of 'a' in a/4 is 1/4, because on multiplying a with 1/4, we get a/4.

The coefficient of c in 2a + 4b + 3c + 10d is 3.

The coefficient is the number in front of the specified variable.

In the equation, the coefficient of c is 3 and the coefficient of a is 2