Помогите 478(a,b)475 и 476

Question

Помогите 478(a,b)475 и 476

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Answer 1

475.
V=4/9×3/4×1/3=1/9(м)
478.
а)=9/56-(28/60-25/60)×(3/14+7/14)=9/56-(1/20×10/14)=9/56-1/28=9/56-2/56=7/56=1/8
б)=(16/24+21/24-20/24)×(17/17-5/17)=17/20×12/17=3/5