Can someone explain this to me? solve step by step. i don't know how to do this.

3. solve by graphing: y = 2x + 6 x + y = -3

Question 6 (10 points) ✓ saved what is the center of a circle described by the equation x2 + y2 +10y = -16? . (0,-5) (0,5) (-5,0) (5,0)

Acar started driving from city a to city b, distance between which is 620 miles, at a rate of 60 mph. two hours later a truck left city b and started moving towards city a at a rate of 40 mph. what distance from city a is the point where the truck and the car will meet?