Question

Să se afle x din proporțiile​

Answer 1

a)

                                         $\frac{3}{x+4}=\frac{6}{18}\\ \Rightarrow 3\cdot 18=6\cdot(x+4)\\ \Rightarrow 3\cdot 18=6x+24\\\Rightarrow 54=6x+24\\\\\Rightarrow 54-24=6x\\\Rightarrow x=\frac{30}{6}=5$

b)

                                   $\frac{3x-4}{0.2}=\frac{0.625}{0.875}\\\Rightarrow (3x-4)\cdot 0.875=0.2\cdot 0.625\\\\\Rightarrow (3x-4)\cdot\frac{875}{1000}=\frac{2}{10}\frac{625}{1000}\\\Rightarrow\frac{2625x}{1000}-\frac{3500}{1000}=\frac{1250}{10000}\\\Rightarrow \frac{26250x-35000}{10000}=\frac{1250}{10000}\\\Rightarrow 26250x-35000=1250\\\Rightarrow 26250x=36250\\\Rightarrow x=\frac{29}{21}$

Answer 2

Aici ai rezolvarea de la subpunctul a