A math assignment question for algebra i dont understand

Fiona and her friends are playing a game by guessing where a coin will land when it is randomly dropped inside the square shown below. fiona guesses that the coin is likely to land in the blue area. which explains whether or not fiona is correct and why?

Find an equation for the linear function which has slope -10 and x-intercept -7

Ineed to know the answer right now! !