4,9х+10х=93,87
14,9х=93,87
х=6,3
1)1/9 - 5 1/3 = 10/9 16/3 =(10 × 1 - 16 × 3)/9 = 10/9 - 48/9 = - 38/9 = - 4 2/9
2) -1/5 + 2,1 = -1/5 + 2 1/10=- 1/5 + 21/10 = (-1 × 2 + 21 × 1)/10 = -2/10 + 21/10 = 19/10 = 1 9/10
3)- 4 2/9 ÷ 1 9/10 = - 38/9 ÷ 19/10 = - 38/9 × 10/19 = - 20/9 = - 2 2/9
ОТВЕТ : - 2 2/9
P=2(6+(6+7))=2(6+13)=2*19=38 см
S=6*(6+7)=6*13=78см²
23x=529
x=529/23
х=23 ================