Jen, a biologist, is growing bacterial cultures at different temperatures as part of her research. The number of cells in the culture growing at 25 °C is given by the polynomial t^2 + 4t + 4, where t is the time elapsed in minutes. The number of cells in the second culture growing at 35°C is modeled by the polynomial t^2 + 4. She needs to measure the sSuccess of the 25 °C culture over the 35 °C culture. Find the polynomial representing how many more cells are in the 25 °C culture for time t. How many more cells are there after 15 minutes?