Final answer:
The equation y = (450 - 15x)(8 + 0.85x) can be used to find Sarah's weekly sales income in dollars, y, after x price increases of $0.85.
Step-by-step explanation:
The equation that can be used to find Sarah's weekly sales income in dollars, y, after x price increases of $0.85 is:
y = (450 - 15x)(8 + 0.85x)
In this equation, x represents the number of price increases of $0.85, and y represents Sarah's weekly sales income. The equation takes into account the decrease in the number of fruit trays sold for every $0.85 increase in the price.