Answer:
D.
Step-by-step explanation:
There is no explanation
always because the opposite of a positive is a negative, and the opposite of a positive is a negative. But zero is neither positive or negative, therefore is has no real opposite and is zero.
Answer:

Step-by-step explanation:
Distribute 3x

Answer:
the right answer is 170
Step-by-step explanation:
so the 90° angle had been divided into 2 so x is 45°
therefore 45×4 is 180 -10= 170