What is the solution? 21=42−3r

may you me ! make sure you are right before answering! : )

Which equations represents circles that have a diameter of 12 units and a center that lies on the y-axis? check all that apply

The median of a data set is the measure of center that is found by adding the data values and dividing the total by the number of data values that is the value that occurs with the greatest frequency that is the value midway between the maximum and minimum values in the original data set that is the middle value when the original data values are arranged in order of increasing (or decreasing) magnitude

Asap! i'm not good math and i'm lost.