The calorie count of a serving of food can be computed based on its composition of​ carbohydrates, fat, and protein. The calorie count C for a serving of food can be computed using the formula C=4h+7f+5​p, where h is the number of grams of carbohydrate contained in the​ serving, f is the number of grams of fat contained in the​ serving, and p is the number of grams of protein contained in the serving. Solve this formula for​ f, the number of grams of fat contained in a food serving.