Pls explain I have an exam in a bit

Step-by-step explanation:

From the picture attached,

In triangle ACD,

Side AB is the extended to form line AC.

(None other side of triangle ACD has been extended).

Therefore, ∠1 will be the exterior angle of ΔACD.

And its remote interior angles of the triangle will be ∠5 and ∠6.

the entire expression should be subtracted from 30. to subtract the quantity, distribute the negative sign, which changes the signs on the terms. so, the –2 changes to positive and gets added to 30 instead of subtracted from it.

hope this ! ^w^