Can you help me with this I need a correct answer

Prove that the value of the expression 7^8–7^7+7^6 is divisible by 43.

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 is the interquartile range of this day at set?