Answer:Just solve it. This is Algebra. Not that hard. Use Substation Method
Step-by-step explanation:
Answer:
x=6, AB=61, BC=61, AC=122
Step-by-step explanation:

X = 20
First, you move the 40 to the other side.
-2x=-40
Then, you divided -40 by -2.
x= -40/-2
x= 20
x is 20 because the negatives cancel out making it positive.