Question

Помогите решить (обе буквы), даю 22 балла.

Answer 1

а)
$\frac{17}{4.3 - c} = 5.1 \\ 4.3 - c = 17 \div 5.1 \\ 4.3 - c = 17 \div \frac{51}{10} \\ 4.3 - c = 17 \times \frac{10}{51} \\ 4.3 - c = \frac{10}{3} \\ c = 4.3 - \frac{10}{3} = \frac{43}{10} - \frac{10}{3} = \frac{129}{30} - \frac{100}{30} = \frac{29}{30}$
б)
$\frac{0.4}{c - \frac{3}{4} } = 1 \frac{1}{3} \\ c - \frac{3}{4} = 0.4 \div 1 \frac{1}{3} \\ c - \frac{3}{4} = \frac{4}{10} \div \frac{4}{3} \\ c - \frac{3}{4} = \frac{4}{10} \times \frac{3}{4} \\ c - \frac{3}{4} = \frac{3}{10} \\ c = \frac{3}{10} + \frac{3}{4} = \frac{6}{20} + \frac{15}{20} = \frac{21}{20} = 1 \frac{1}{20}$

Answer 2

$a)\; \; \frac{17}{4,3-c}=5,1\\\\17=5,1(4,3-c)\\\\17=21,93-5,1c\\\\5,1c=4,93\\\\c=\frac{4,93}{5,1}=\frac{493}{510}\; \Big |\frac{:17}{:17}\\\\c=\frac{29}{30}$

$b)\; \; \frac{0,4}{c-\frac{3}{4}}=1\frac{1}{3}\\\\\frac{4}{10\cdot \frac{4c-3}{4}}=\frac{4}{3}\; \Big |:4\\\\\frac{4}{10(4c-3)}=\frac{1}{3}\\\\\frac{2}{5(4c-3)}=\frac{1}{3}\\\\2\cdot 3=5(4c-3)\\\\6=20c-15\\\\20c=21\\\\c=\frac{21}{20}\\\\c=1,05$