Where my beans at homie

The weight of full–grown tomatoes at a farm is modeled by a normal distribution with a standard deviation of 18.4 grams. the 95 percent confidence interval for the mean weight of the tomatoes is calculated using a sample of 100 tomatoes. what is the margin of error (half the width of the confidence interval)?

If 5x - 2 = -12, then x = a) -50 b) -4.4 c) -2.8 d) -2

Can someone tell me if these are correct?