5/12+3. И. 1+5/7. 30 баллов!!!!!

 [latex] \frac{5}{12} [/latex] + 3 = [latex] \frac{5}{12} [/latex] + [latex] \frac{36}{12} [/latex] = [latex] \frac{41}{12} [/latex] = 3 [latex] \frac{5}{12} [/latex] 1 + [latex] \frac{5}{7} [/latex] = [latex] \frac{7}{7} [/latex] + [latex] \frac{5}{7} [/latex] = [latex] \frac{12}{7} [/latex] = 1 [latex] \frac{5}{7} [/latex]