They are called vertical angles because the definition of vertical is: <span>in a direction, or having an alignment, such that the top is directly above the bottom. The "angles opposite each other when two lines cross" match the definition.</span>
Answer:

Step-by-step explanation:



20 less than (-20) a number (n) is more than (>) twice the same number (2n)
-20+n>2n
minus n both sides
-20>n
n<-20
Answer:
X+4
Step-by-step explanation:
8+3x=25-x
3x+x=24-8
4x+16