750:(81-х)+27=42 и 39×(288:a)=312

Question

750:(81-х)+27=42 и 39×(288:a)=312

Answer 1

750:(81-х)+27=42
750:(81-х)=42-27
750:(81-х)=15
81-х=750:15
81-х=50
х=81-50
х=31
750:(81-31)+27=42


39х(288:а)=312
288:а=312:39
288:а=8
а=288:8
а=36
39х(288:36)=312