The expansion by the binomial theorem of ( 2 x + 1 / 8) to the power of 10 is 1024x to the power of 10 + 640x to the power of 9 + ax to the power of 8 + bx to the power of 7 +...... Calculate coefficient of x to the power of 8 in ( 3 x - 2) ( 2 x + 1 / 8) to the power of 10?