Whats a constant and a variable and a coeffecient?

A constant is a number, or a letter that represents a number that

never changes. From the time the problem starts until as long

as it lasts, its value is constant.

A variable is a letter that stands for a number that can change.

A coefficient is each of the items in a group of them that are all

multiplied together.

Example: 17x + 4y

That's an expression with two terms.

The terms are '17x' and '4yz'.

In the first term:

'17' is the numerical coefficient.

'x' is the literal coefficient.

In the second term:

'4' is the numerical coefficient.

'y' and 'z' are both literal coefficients.