let's firstly convert the mixed fraction to improper fraction, and then divide.
5(x-1) + 3 = 13
5x - 5 + 3 = 13
5x -2 = 13
5x = 15
x = 15/5
x = 3
Answer:
(-8,-4) and (-2,5). at reflect on x axis
Let 0.25x is the price increase. Therefore, the number of attendees will be 350-10x and the revenue R=(350-10x)*(5+0.25x)=1750+37.5x-2.5x^2. This parabola has maximum at x=10, meaning the price=7.5