Can someone me explain circumfrence to my friend

Mary beth used the mapping rule to find the coordinates of a point that had been rotated 90° counterclockwise around the origin. examine the steps to determine whether she made an error. m (3, –6) is rotated 90° counterclockwise. (x, y) → (–y, x) 1. switch the x- and y-coordinates: (6, –3) 2. multiply the new x-coordinate by –1: (6(–1), –3) 3. simplify: (–6, –3) .

Determine the difference: 3.2 × 1010 – 1.1 × 1010. write your answer in scientific notation.

50 points~ ! i have to turn this in tomarrow