How to solve a? I don’t k ow what I’m doing wrong

The number of potato chips in a bag is normally distributed with a mean of 71 and a standard deviation of 2. approximately what percent of bags contain between 69 and 73 potato chips? approximately 68% approximately 71% approximately 95% approximately 99.7%

What is the range? can’t seem to find it out

Solve for x and y: 217x + 131y = 913; 131x + 217y = 827