Someone pls answer all of these if you know it thank you!

Simplify 15(x - 4)(x -1)-3(x + 4)(x - 1) with steps

In the diagram of circle o, what is the measure of zabc?

The mean finish time was 185.52 with a standard deviation of 0.327 minute. the winning car driven by chris finished in 185.13. the previous year race had a mean finish time of 110.3 with a standard deviation of 0.106. the winning car that year driven by karen finished in 110.13 minutes. find their respective z-scores. chris - z-score karen “- z-score