What is the slope of the line that passes through the points (6,4) and (-3,-7)

X-intercept=-5 y-intercept=2 the equation of the line is

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?

How do you write something in scientific notation?