Answer:
Yes. It should be y= – 10x+50 
This is in standard form, and it means that for every hour (x) you decrease by 10, starting point being 50. Y=50-10x wouldn’t be in standard form so I just moved it around. 
You can use a linear model to represent the car’s speed as a function of time because the speed linearly decreases over time at an initial speed of 50mph, so y=–10x+50. 
The value for the slope is –10, because the car’s speed is decreasing linearly. 
The y intercept can be found when you substitute 0 for x. 
-10(0) +50 
Y intercept = 50 
This means that at 0 hours, the cars speed is 50 mph.
Explanation:
this is what the tutor person said and i entered it in and got 100% so go with that