What is the math term for you taking parentheses away?

You might be thinking of "distribution" or "distributive property"

Example:

2 (3x+5) = 2*3x+2*5 = 6x+10

I multiplied the outer 2 by each term inside (3x and 5)

Distributive property

Step-by-step explanation:

Remark

Usually it is the Distributive property. There has to be a plus or minus sign that connects two or more terms that can't be reduced any further.

Example One

5 (x + y + 2) Three terms which cannot be added together.

5x + 5y + 10 Distributive Property.

Example Two

- x (2y + 3x^2 - 4)

-2xy - 3x^3 + 4x Distributive Property