Answer:
18p-12=20 I checked for you
Hey there :)
9( n - 4 ) - 4n ( n - 4 )
We can take ( n - 4 ) as common as both are getting multiplied by ( n - 4 )
We can join 9 - 4n together
Therefore, the final answer will be ( n - 4 )( 9 - 4n )
The 2 angles at a vertex are supplementary (one interior and one exterior) the exterior angle is = the sum of the 2 remote interior angles - I hope this helps.