Test the continuity of​

Which equation can be used to solve for the unknown number? seven less than a number is thirteen. n-7=13 7-n=13 n+7=13 n+13=7

He weights of 2-pound bags of best dog food are approximately normally distributed with a given mean  and standard deviation  according to the empirical rule, what percentage of the bags will have weights within 3 standard deviations of the mean? 47.5%68%95%99.7%

What function has a range {yly< 5}? question on picture above^