Fill in the blank.
A letter (unknown) is also called a _____________ in math.

Simplify.
2x+3x

The number in front of a variable is called a ____________________ .

Simplify.
4(x^2)+5-6-2(x^2)

*x^2 = x squared

The degree is also known as an _____________________ .

x^3 - 7x^3 + x^2

___________________ is separated by addition or subtraction.

_____________ has an equal to sign.