Please help I’m confused

What is the value of the expression 9+n/3-6 when n = 12? 1. 5. 7. 12.

The brain volumes (cm cubed) of 50 brains vary from a low of 904 cm cubed to a high of 1488 cm cubed. use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.5 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed

Write a function for a rotation 90 degrees counter clockwise about the origin, point 0