Start off by combining like terms (your y's).
7y - 6y - 10 = 13
y - 10 = 13
Now you need to get y by itself so add 10 to both sides
y - 10 = 13
+10 +10
y = 23
Answer: Angle 4
Step-by-step explanation:
The angle of depression is formed by the line of sight and the horizontal line tangent to the top of the observer.
