I NEED HELP ASAP about this question it’s for a test !

Simplify (a/b - b/a) times (a - a^2/a+b) a - a^2/a=b is a mixed number

Long division the problem is 40 ➗ 348 = ?

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%