Question

daca x/y=4/5 atunci 3x+5y/5x-3y=...?

Answer 1

      
$Fractia:\;\;\; \frac{3x+5y}{5x-3y},\;\;\;o \;simplificam\;fortat\;cu\; y \\ \\ \frac{3x+5y}{5x-3y}= \frac{3 \frac{x}{y} +5 \frac{y}{y} }{5 \frac{x}{y} -3 \frac{y}{y}}= \frac{3 \frac{x}{y} +5 }{5 \frac{x}{y} -3}= \frac{3 \frac{4}{5} +5 }{5 \frac{4}{5} -3}=\frac{\frac{12}{5} +5 }{\frac{20}{5} -3}= \\ \\ =\frac{\frac{12+25}{5} }{\frac{20-15}{5}}=\frac{12+25}{5} *\frac{5}{20-15} =\frac{12+25}{20-15}= \boxed{\frac{37}{5}}= \boxed{7,4}$