170cos (arccos 4/5 - acrsin8/17) = 170[cos(arccos4/5)*cos(arcsin8/17) + sin(arccos4/5)*sin(arcsin8/17)] = 170{(4/5)*√(1- 8²/17²) + (8/17)* √(1- 4²/5²)} =
= 170{(4/5)*(15/17) + (8/17)*(3/5)} =170*84/85 = 168
ответ: 168
