1)476+а+224=700+а=700+221=921
2)х+246-46=х+200=137+200=337
3)973-243-у=730-у=730-258=472
5*(с+3):6=8*(10-с):6
(5с+15):6=(80-8с):6 умножим обе стороны на 6 и получим
5с+15=80-8с
5с+8с=80-15
13с=65
с=65/13
с=5
▪5/8 - 3/4 = 5/8 - 6/8= -1/8
▪4/7 • 14/15 = (4×14)/(7×15) = (4×2)/15 = 8/15
▪20/27:5/6 = 20/27 × 6/5 = (4×2)/9 = 8/9
(9- 2 2/3*2 1/7)*21/46=
1) 2 2/3 * 2 1/7=8/3* 15/7= 40/7=5 5/7
2) 9 - 5 5/7=3 2/7
3) 3 2/7 * 21/46=23/7*21/46=3/2=1 1/2
45 - 90:3 = 15 15 ответ:15