Given that lona is riding her bike to the park that means Her distance from the park is decreasing so we will use negative sign for the slope.
She is rides at the rate of 15 mph so that means slope is m=-15
She starts 8 miles from the park so that means initial distance b=8
now plug both into formula y=mx+b to get the equation
We get:
y=-15x+8
Hence final answer is y=-15x+8.