Currently, an artist can sell $260$ paintings every year at the price of ${\$140.00}$ per painting. Each time he raises the price per painting by ${\$10.00}$, he sells $5$ fewer paintings every year. Assume the artist will raise the price per painting $x$ times. The current price per painting is ${\$140.00}$. After raising the price $x$ times, each time by ${\$10.00}$, the new price per painting will become $140+10x$ dollars. Currently he sells $260$ paintings per year. It’s given that he will sell $5$ fewer paintings each time he raises the price. After raising the price per painting $x$ times, he will sell $260-5x$ paintings every year. The artist’s income can be calculated by multiplying the number of paintings sold with price per painting. If he raises the price per painting $x$ times, his new yearly income can be modeled by the function: where $f(x)$ stands for his yearly income in dollars. Answer the following questions: 1) To obtain maximum income of , the artist should set the price per painting at . 2) To earn ${\$43{,}200.00}$ per year, the artist could sell his paintings at two different prices. The lower price is per painting, and the higher price is per painting.