Question

545.
1)28/67×(а-2 11/13÷b)÷c
а=10 11/13 b=1/2 c=3 1/2;
2)(12÷а+b)÷1 /12-c
a=3 3/5 b=2/3 c=1 1/3.​

Answer 1

Ответ:

1) 28/67×(а-2 11/13÷b)÷c.

а = 10 11/13, b = 1/2, c = 3 1/2.

$\frac{28}{67}*(a-2\frac{11}{13}:b):c= \frac{28}{67}*(10\frac{11}{13} -2\frac{11}{13}:\frac{1}{2} ):3\frac{1}{2} = \\\\= \frac{28}{67}*(\frac{13*10+11}{13} -\frac{13*2+11}{13}*2 ):\frac{2*3+1}{2} = \frac{28}{67}*(\frac{141}{13} -\frac{37}{13}*2 ):\frac{7}{2} = \frac{28}{67}*(\frac{141}{13} -\frac{74}{13} )*\frac{2}{7} = \\\\= \frac{28}{67}*\frac{67}{13}*\frac{2}{7} =\frac{4}{67}*\frac{67}{13}*2=4*\frac{1}{13}*2=\frac{8}{13}.$

2) (12÷а+b)÷1 1/2-c.

a = 3 3/5, b = 2/3, c = 1 1/3.

$(12:a+b):1\frac{1}{2} - c= (12:3\frac{3}{5} +\frac{2}{3} ):1\frac{1}{2} -1\frac{1}{3}=(12:\frac{5*3+3}{5} +\frac{2}{3} ):\frac{2*1+1}{2} -\frac{3*1+1}{3}=\\\\=(12:\frac{18}{5} +\frac{2}{3} ):\frac{3}{2} -\frac{4}{3}= (12*\frac{5}{18} +\frac{2}{3} )*\frac{2}{3} -\frac{4}{3}= (2*\frac{5}{3} +\frac{2}{3} )*\frac{2}{3} -\frac{4}{3}= \\\\=(\frac{10}{3} +\frac{2}{3} )*\frac{2}{3} -\frac{4}{3}=\frac{12}{3} *\frac{2}{3} -\frac{4}{3}= 4*\frac{2}{3} -\frac{4}{3}= \frac{8}{3}-\frac{4}{3}=\frac{4}{3}=1\frac{1}{3}.$