Help plzzz
Which of the following is NOT an equivalent expression to Area of sector =

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

Can someone check if i did this correct. it’s number 4 if you’re wondering.

What is the sum of 25x + 15y and (-18x - 6y)