If 3x + 8 = 5x - 6, then what is the value of 10x?

What is the size of the matrix resulting from

How to do this , and can some one explain

The means and mean absolute deviations of the individual times of members on two 4x400-meter relay track teams are shown in the table below. means and mean absolute deviations of individual times of members of 4x400-meter relay track teams team a team b mean 59.32 s 59.1 s mean absolute deviation 1.5 s 245 what percent of team b's mean absolute deviation is the difference in the means? 9% 15% 25% 65%