A motorboat moves across a lake. It begins at 50km from shore after 9 minutes it is 14 km from shore. What’s it’s distance from shore in a function

y = -4x + 50

Step-by-step explanation:

To write the function we'll use y = mx + b, where y is the distance the boat is away from shore, m is how many km/minute the boat moves at, x is how many minutes it's been, and b is how many km away from shore the boat was at the start. We already know the value of b is 50, so we can put that into the equation:

y = mx + 50

To find how many km the boat moves per minute, let's use the given amount of minutes and km (9, 14) and put them into the equation:

14 = m(9) + 50

Now let's solve for m:

14 = 9m + 50

Subtract 50 from both sides to isolate the 9m:

14 - 50 = 9m + 50 - 50

- 36 = 9m

divide both sides by 9 to isolate the m:

-36/9 = 9m/9

-4 = m

The boat moves at -4 km/minute, which is the same thing as saying that  after 1 minute passes, the boat gets 4km closer to the shore. Now we can input this value into the equation and we have our

y = -4x + 50