Question

x/3+x/5=1
como faço a conta?

Answer 1

Ae Emanuel, preste atenção..

$\dfrac{x}{3} + \dfrac{x}{5}=1\\\\ \dfrac{x}{3}+ \dfrac{x}{5}= \dfrac{3}{3}\\\\ MMC~de~3~e~5=15\\\\ \dfrac{5\cdot x+3\cdot x}{\not15}= \dfrac{3\cdot5}{\not15}\\\\ 5x+3x=15\\ 8x=15\\\\ x= \dfrac{15}{8}\\\\ tirando~a~prova:\\\\ \dfrac{ \dfrac{15}{8} }{3}+ \dfrac{ \dfrac{15}{8} }{5}=1\\\\ \dfrac{15}{8} \div \dfrac{3}{1} + \dfrac{15}{8}\div \dfrac{5}{1} =1\\\\ \dfrac{15}{8}\cdot \dfrac{1}{3}+ \dfrac{15}{8}\cdot \dfrac{1}{5} =1$

$\dfrac{15}{24}+\dfrac{15}{40}=1\\\\\dfrac{15\cdot40+15\cdot24}{24\cdot40} =1\\\\ \dfrac{600+360}{960}=1\\\\\dfrac{960}{960}=1$

Pronto!