What is 2x plus -2x?

2x + - 2x = 0 (zero)

Remember when you have two opposite signs, treat it as negative (-).

Also the 'x' is an unknown but fixed amount, so the 'x' in '2x' could be '3', so the 'x' in '-2x' is ALSO '3'.

Hence

2(3) + - 2(3) =

6 - 6 = 0

NB

For mixed signs#

• • = +
• • = -

• • = -
• • = +