29. Calculează:
a) (150–5∙1)·(150-5-2). (150-5-3)..... (150-5.30);
b) (41-5.1) (42-5-2) (43-5-3).... (55-5.15);
c) (15-0.9). (16-1.8) (17-2-7)... (24-9.0). ​