1/5+8/25+7/25=       1/7+2/21+3/7=    1/15+2/45+7/15=     3/49+5/7+4/49=   7/10+2/15+11/30=   1/12+1/18+1/12=  помагите пожалуйста срочно надо

5/25 + 8/25 + 7/25 = 20/25 = 4/5
3/21 + 2/21 + 9/21 = 14/21 = 2/3
3/45 + 2/45 + 21/45 = 26/45
3/49 + 35/49 + 4/49 = 42/49 = 6/7
21/30 + 4/30 + 11/30 = 36/30 = 6/5
3/36 + 2/36 + 3/36 = 8/36 = 2/9