Question

select the two properties that justify equating the expressions.
$(10 + (-10)) + 7x$
$= 0 + 7x$
$= 7x$
show your work here

Explanation:

1. The step from $(10 + (-10)) + 7x$ to $0 + 7x$ uses the property that the sum of a number and its additive inverse equals 0.
2. The step from $0 + 7x$ to $7x$ uses the property that adding 0 to a number leaves the number unchanged.

Answer:

1. Additive Inverse Property (the sum of a number and its opposite is 0)
2. Additive Identity Property (adding 0 to a number does not change the number)