We know that the opposite is the additive inverse.
For example, 8+(−8)=0 where 0 is the identity for addition.
Given that we have to compute the sum of 5x+20 and the opposite.
Given
5x+20
opposite of 5x+20 = -(5x+20)
so
The sum of 5x+20 and the opposite:
5x+20 + -(5x+20)
Distribute the Negative Sign
Combine Like Terms
Therefore, the sum of 5x+20 and the opposite is: 0
Thus, the equivalent expression is: