15x+21=51
15x=30
x=2 otvet 2
4:3=1 ост. 1. если помог, поблагодари:-)
Решение:
12<span>27</span> - 6<span>35</span> = 6 + <span>27</span> - <span>35</span> = 6 - <span>2·57·5</span> - <span>3·75·7</span> = 6 + <span>1035</span> - <span>2135</span> = 6 + <span>10 - 2135</span> = 6 - <span>1135</span> = <span>6·3535</span> - <span>1135</span> = <span>19935</span> = <span>24 + 5·3535</span> = 5<span>2435</span> ≈ 5.685714285714286